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Psychostimulants activate the Ras-mitogen-activated protein kinase (Ras-MAPK) cascade in the limbic reward circuit and thereby trigger a transcription-dependent mechanism underlying enduring synaptic plasticity related to addictive properties of drugs of abuse. The Ras-specific activator, Ras-guanine nucleotide-releasing factor (Ras-GRF), is predominantly expressed at synapses and is thought to actively regulate Ras-MAPK responses to changing synaptic signals. In this study, a possible influence of cocaine on Ras-GRF gene expression at the protein level in the rat striatum was investigated in vivo. A single systemic injection of cocaine induced an increase in Ras-GRF1 protein levels in both the dorsal (caudoputamen) and ventral (nucleus accumbens) striatum. The increase in Ras-GRF1 proteins was dose-dependent and was a delayed and transient event. In contrast to Ras-GRF1, a closely related Ras-GRF2 showed no change in its protein abundance following cocaine administration. These data identify the Ras activator, Ras-GRF1, although not Ras-GRF2, as a susceptible target to cocaine stimulation in striatal neurons.

The transcription factor cAMP response element-binding protein (CREB) promotes target DNA transcription in response to cellular stimulation in brain neurons. Phosphorylation of CREB is regulated by a variety of extracellular and intracellular signals. In this study, protein kinase C (PKC)-regulated CREB phosphorylation was investigated in cultured rat striatal neurons. We found that PKC activation with phorbol 12-myristate 13-acetate (PMA) produced a rapid and transient phosphorylation of CREB. The increase in CREB phosphorylation was dose-dependent and prevented by the two PKC selective inhibitors (chelerythrine and Gö6983). Interestingly, the PMA-induced CREB phosphorylation was also blocked by a calcium/calmodulin-dependent protein kinase inhibitor KN93 and the two mitogen-activated protein kinase (MAPK) kinase inhibitors PD98059 and U0126, but not by a p38 MAPK inhibitor SB203580. PMA activation of PKC markedly increased phosphorylation of MAPK/extracellular signal-regulated kinase 1/2. The protein kinase A (PKA) inhibitor H89 at a dose that completely blocked the PKA activator (8-br-cAMP)-induced CREB phosphorylation partially blocked the PMA-stimulated CREB phosphorylation. Furthermore, blockade of NMDA and AMPA glutamate receptors and L-type voltage-operated Ca(2+) channels did not alter the ability of PMA to induce CREB phosphorylation. These results demonstrate that PKC is among the protein kinases that can positively modulate CREB phosphorylation in striatal neurons, and the PKC signals to CREB activation are mediated via signaling mechanisms involving multiple downstream protein kinases.

Background Despite high levels of equipment distribution through Needle and Syringe Programmes (NSPs) in Australia, the levels of reuse of equipment among people who inject drugs remain concerning. This paper used an exploratory analysis to examine the needs of NSP client that could be addressed by NSPs to enhance service impact and blood-borne virus risk practices. Methods People who inject drugs were recruited from six NSP sites in Sydney, Australia, to undertake a self-completed survey. Results Using the responses of 236 NSP client participants, three factors were identified in an exploratory factor analysis: recent risky injection (Eigenvalue 3.63, 20.2 % of variance); disadvantage and disability (Eigenvalue 2.26, 12.5 % of variance); and drug use milieu (Eigenvalue 1.50, 8.4 % of variance). To understand the distribution of these factors, the standardised factor scores were dichotomised to explore those participants with ‘above average’ vulnerability on each factor. A small group of NSP clients reported a cluster of vulnerability measures. Most participants (55.5 %) reported vulnerability on none or only one factor, indicating that 45.5 % could be considered as having double (35.6 %) or triple (8.9 %) vulnerability. Conclusions These results challenge NSPs to understand the heterogeneity among their client group and develop programmes that respond to their clients’ range of needs beyond those immediately associated with blood-borne virus (BBV) risk. This paper contributes to the growing evidence base regarding the need for BBV prevention efforts to examine strategies beyond equipment distribution.

With the expanding pharmaceuticalization of public health, anthropologists have begun to examine how biomedicine's promissory discourses of normalization and demarginalization give rise to new practices of and criteria for citizenship. Much of this work focuses on the biomedicine-citizenship nexus in less-developed, resource-poor contexts. But how do we understand this relationship in resource-rich settings where medicines are readily available, often affordable, and a highly commonplace response to illness? In particular, what does it mean to not use pharmaceuticals for a treatable infectious disease in this context? We are interested in these questions in relation to the recent push for early and universal treatment for HIV infection in Australia for the twin purposes of individual and community health. Drawing on Ecks's concept of pharmaceutical citizenship, we examine the implications for citizenship among people with HIV who refuse or delay recommended medication. We find that moral and normative expectations emerging in the new HIV "treatment revolution" have the capacity to both demarginalize and marginalize people with HIV.

The snake-like robot underwater motion performance is analyzed in computational fluid dynamics method. The mathematical and numerical model of the robot with fluid turbulent motion in flow field is presented. The positive pressure of the flow field around robot head is rendered as streamlined and its tail presents a very strong vortex phenomenon. The configuration of the robot should be designed as streamline structure to improve its motion performance.

Gay and other men who have sex with men (GMSM) are disproportionally affected by the HIV epidemic in Australia. The study objective is to combine a clinical-based cohort with a community-based surveillance system to present a broader representation of the GMSM community to determine estimates of proportions receiving antiretroviral therapy (ART) and/or with an undetectable viral load. Between 2010 and 2012, small increases were shown in ART uptake (to 70.2%) and proportions with undetectable viral load (to 62.4%). The study findings highlight the potential for significantly increasing ART uptake among HIV-positive GMSM to reduce the HIV epidemic in Australia.

We analyzed the HIV risk reduction strategies (RRS) used by Australian gay and bisexual men with casual partners. Among 1346 men who reported any condomless anal intercourse with casual partners, 75% frequently practiced at least one RRS. The most common RRS was serosorting, frequently practiced by 55% of HIV-positive and 47% of HIV-negative participants. Condoms were frequently (but inconsistently) used by 17% of HIV-positive, 41% of HIV-negative, and 30% of untested participants. Relying on an undetectable viral load was frequently practiced by 58% of HIV-positive participants. Strategic positioning, withdrawal, and non-HIV-positive men taking antiretroviral medication were less common strategies.

Src and Fyn are two Src family kinase (SFK) members that are expressed in mammalian brains and play important roles in the regulation of a variety of neuronal and synaptic substrates. Here we investigated the responsiveness of these SFKs to changing dopamine receptor signals in dopamine responsive regions of adult rat brains in vivo. Pharmacological activation of dopamine D1 receptors (D1Rs) by a systemic injection of the selective agonist SKF81297 increased phosphorylation of SFKs at a conserved and activation-associated autophosphorylation site (Y416) in the striatum, indicating activation of SFKs following SKF81297 injection. The dopamine D2 receptor (D2R) agonist quinpirole had no effect. Blockade of D1Rs with an antagonist SCH23390 did not alter striatal Y416 phosphorylation, while the D2R antagonist eticlopride elevated it. Between Src and Fyn, SKF81297 seemed to preferentially facilitate Fyn phosphorylation. Activation of muscarinic acetylcholine M4 receptors (M4Rs) with a positive allosteric modulator VU0152100 suppressed SFK Y416 responses to SKF81297. Additionally, SKF81297 induced a correlated increase in phosphorylation of N-methyl-D-aspartate (NMDA) receptor GluN2B subunits at a Fyn site (Y1472), which was attenuated by VU0152100. SKF81297 also enhanced synaptic recruitments of active Fyn and GluN1/GluN2B-containing NMDA receptors. These data demonstrate that D1Rs regulate Fyn and downstream NMDA receptors in striatal neurons in vivo. Acetylcholine through activating M4Rs inhibits Fyn and NMDA receptors in their sensitivity to D1R signaling.

In order to launch a soccer game between human and robots, one of the crucial problems for robots is to effectively identify human and their actions. In this paper, based on human skeleton tracking information from Kinect, GR (Gesture Recognition), FVGR (Front View Gait Recognition) and NNVGR (Non-Normative View Gait Recognition) are carried out to develop the HRI (Human Robot Interaction) systems for a middle size league soccer robot. This method is used to identify the human body language and obtain information of body movements, so that the HRI system can generate different command to control the movements of the middle size league soccer robot. The performances of the proposed HRI systems are verified by different experiments. The experimental results show that this method can quickly and safely identify human and their movements. This research can provide a practical solution for Mid-Sized League competition between human and robots in the future.

In order to understand the mechanism of artificial CPG (Central Pattern Generator) neuron system for the locomotion control of snake-like robot, a MNSM (Mirror Neuron System Mechanism)-based controller is developed for swimming locomotion in this paper. In this neuron system, the rhythmic swimming motion generated by CPG neuron network is perceived by another MNSM-based controller, and it generate similar output of the CPG controller to drive the robot to realize the same swimming motion of the robot.

Introduction : Studies in heterosexual HIV serodiscordant couples have provided critical evidence on the role of HIV treatments in reducing HIV transmission risk. However, there are limited data regarding the effect of treatment on HIV transmission in homosexual male couples. We examined features of male homosexual HIV serodiscordant relationships that may impact upon the design of HIV treatment and transmission studies. Methods : Data were from a prospective cohort study of HIV-negative homosexual men in Sydney, Australia. Men were followed up with six-monthly interviews and annual testing for HIV. Characteristics of men in HIV serodiscordant and seroconcordant relationships at baseline were compared, and a longitudinal analysis performed of rate of relationship break-up and of HIV incidence. Results : At baseline, 5.5% of participants ( n =79) had an HIV-positive partner. Most (80.8%) of these relationships were non-monogamous, and 36.7% of men reported recent unprotected anal intercourse (UAI) with casual partners. The rate of relationship break-up was 29.5 per 100 person-years. Half of men in serodiscordant relationships (49.4%) reported recent UAI with their regular partners. HIV incidence was 2.2 per 100 person-years. It was substantially higher in relationships of less than one year’s duration (6.1 per 100 person-years) and in men who reported unprotected receptive anal intercourse with ejaculation with their regular partners (15.5 per 100 person-years). Conclusions : Levels of HIV transmission risk and incidence were high, particularly in early relationships. Rates of relationship break-up were high. These data suggest that studies of HIV treatments and transmission in homosexual serodiscordant couples should focus on early relationships so as not to underestimate risk, and sample sizes must allow for high rates of relationship break-up. Keywords: HIV treatment as prevention; men who have sex with men; homosexual men; serodiscordant couples; HIV viral load; HIV transmission. (Published: 25 May 2015) Citation: Bavinton BR et al. Journal of the International AIDS Society 2015, 18 :19884 http://www.jiasociety.org/index.php/jias/article/view/19884 | http://dx.doi.org/10.7448/IAS.18.1.19884

Current debates regarding the use of antiretroviral therapy (ART) to promote both individual- and population-level health benefits underscore the importance of understanding why a subpopulation of people with diagnosed HIV and access to treatment choose not to use it. Semi-structured interviews were conducted between 2012 and 2014 with 27 people living with HIV in Australia who were not using ART at the time of interview. Analytic triangulation permitted an appreciation of not only the varied personal reasons for non-use of treatment, but also underlying views on HIV treatment, and the ideal conditions imagined necessary for treatment initiation. Policy goals to increase the number of people with HIV using ART must recognize the diverse explanations for non-use of ART, which include concerns about the various impacts of committing to lifelong pharmaceutical treatment use. Our research identified distinctive subgroups among people who are not using antiretroviral therapy, with a range of individual and social needs that may affect treatment decisions. These findings challenge assumptions about treatment non-use in resource-rich settings, revealing persistent consumer fears about the potent and unknown effects of HIV medications that deserve greater recognition in policy debate on treatment uptake.

Past research on unprotected anal intercourse with casual partners (UAIC) contrasts those who report no UAIC with any UAIC. This paper examines differences among three groups of men who had any UAIC on the basis of the number of UAIC acts reported in a six-month period, namely no UAIC (n = 507), occasional UAIC (1-5 acts, n = 251) and frequent UAIC (more than 5 acts, n = 148). The occasional UAIC group had values lying between those of the no- and the frequent-UAIC group. As compared with the frequent-UAIC group, men in the occasional-UAIC group were less likely to have a steady partner, held less favorable attitudes toward condoms and higher levels of HIV treatments optimism and were more likely to report some disclosure of serostatus to or by casual partners and a range of esoteric sexual practice. On the other hand, men in the no-UAIC group had lower levels of 'feeling bad' (distress) and were less likely to use drugs to enhance sexual pleasure in casual encounters. Disclosure of serostatus had a strong association with frequent UAIC and this finding calls for both more research and more community exploration of issues surrounding sexual decision-making.

Background: Early detection and treatment of bacterial sexually transmitted infections has been advocated as an HIV prevention strategy. Aim: To inform screening guidelines, the incidence and risk factors for urethral and anal gonorrhoea and chlamydia were studied in a prospective cohort of community-based HIV negative homosexual men in Sydney, New South Wales, Australia. Methods: All participants were offered annual screening for gonorrhoea and chlamydia (study-visit diagnoses) on urine and anal swabs using nucleic acid amplification. Participants also reported diagnoses of gonorrhoea and chlamydia made elsewhere between interviews (interval diagnoses). All diagnoses were summed to create a combined incidence rate, and detailed data on specific sexual practices with casual and regular partners were collected. Results: Among 1427 men enrolled, the combined incidence rates were 3.49 and 2.96 per 100 person-years for urethral and anal gonorrhoea, respectively; and 7.43 and 4.98 per 100 person-years for urethral and anal chlamydia, respectively. Urethral infections were associated with unprotected anal intercourse (UAI) with HIV-positive partners (hazard ratio (HR) = 2.58, 95% CI 1.10 to 6.05 for urethral gonorrhoea) and with frequent insertive oral sex (p for trend 0.007 for urethral chlamydia). Anal infections were associated with receptive UAI (p for trend 0.001 for both anal gonorrhoea and chlamydia) and other receptive anal sexual practices. Stratified analyses showed the independence of the associations of insertive oral sex with urethral infections and of non-intercourse receptive anal practices with anal infections. Conclusion: Incident gonorrhoea and chlamydia were common. Risk behaviours for both urethral and anal infections were not restricted to UAI. Screening that includes tests for anal and urethral infections should be considered for all sexually active homosexual men, not just for those who report UAI.

Background. Despite increasing reports of herpes simplex virus (HSV) type 1 (HSV-1)-associated anogenital herpes, there are very limited data comparing the seroepidemiological profile of and risk factors for HSV-1 and HSV type 2 (HSV-2) infection. Methods. Sexual behaviors were examined as risk factors for prevalent and incident HSV-1 and HSV-2 infections in a community-based cohort of 1427 HIV-negative gay men in Australia. Results. The prevalence of HSV-1 and HSV-2 at baseline was 75% and 23%, respectively. The rate of prevalent infection with HSV-1, as well as the rate of prevalent infection with HSV-2, was much lower in individuals

Background Anesthetics may interact with ionotropic glutamate receptors to produce some of their biologic actions. Cellular studies reveal that the ionotropic glutamate receptors, N-methyl-D-aspartate receptors (NMDARs), can be phosphorylated on their NR1 subunits at the C-terminal serine residues, which is a major mechanism for the regulation of NMDAR functions. It is currently unknown whether anesthetics have any modulatory effects on NMDAR NR1 subunit phosphorylation. Methods The possible effect of a general anesthetic propofol on phosphorylation of NR1 subunits at serine 897 (pNR1S897) and 896 (pNR1S896) was detected in cultured rat cortical neurons. Results Propofol consistently reduced basal levels of pNR1S897 and pNR1S896 in a concentration-dependent manner. This reduction was rapid as the reliable reduction of pNR1S896 developed 1 min after propofol administration. Pretreatment of cultures with the protein phosphatase 2A inhibitors okadaic acid or calyculin A blocked the effect of propofol on the NR1 phosphorylation, whereas okadaic acid or calyculin A alone did not alter basal pNR1S897 and pNR1S896 levels. In addition, propofol decreased tyrosine phosphorylation of protein phosphatase 2A at tyrosine 307, resulting in an increase in protein phosphatase 2A activity. In the presence of propofol, the NMDAR agonist-induced intracellular Ca2+ increase was impaired in neurons with dephosphorylated NR1 subunits. Conclusions Together, these data indicate an inhibitory effect of a general anesthetic propofol on NMDAR NR1 subunit phosphorylation in neurons. This inhibition was mediated through a signaling mechanism involving activation of protein phosphatase 2A.

In recent years, increases in both risk behavior and in seroconversion among homosexually active men have been noted in a number of parts of the world. Data were available from 903 HIV negative homosexual men regarding number of acts of unprotected anal intercourse (UAI), separated into receptive and insertive UAI, with and without ejaculation, with steady and with casual partners. Partners were classified according to serostatus as reported by respondents. Men (N = 325) reported 13,692 UAI acts, most of which were with steady partners, of whom most were reported to be HIV-negative. With HIV-positive partners, both steady and casual, and with casual partners of unknown serostatus, receptive UAI with ejaculation was relatively rare. Insertive UAI without ejaculation was relatively common with casual partners of unknown serostatus. Patterns of UAI suggest that risk of transmission may be greater with steady partners. Men appear to modify practice according to both the nature of the relationship (steady or casual) and (assumed) serostatus of partner.

This paper reports on the breaking of agreements between regular partners among HIV-negative gay men in Sydney. Data were from the 1333 men completing face-to-face interviews through December 2003 for the Health in Men (HIM) open cohort of HIV-negative gay men in Sydney.822 men had a primary regular partner during the six month period before their 2003 interview. Most of these men had entered into agreements with their partners about sex either with each other or with other partners (87.2%). They most commonly agreed not to use condoms with each other (50.6%). Regarding casual sex, they most commonly agreed to always use condoms (34.2%) or to have no sex with men outside their relationships (28.6%). 48.8% reported some discomfort discussing with their partner their sex outside the relationship. Among those with agreements with their partners, 27.7% reported ever breaking those agreements. Those who found it more difficult to discuss issues of HIV serostatus and sexuality were more likely to report having broken their agreements (p.001; p=.021 at one-year follow-up) and were more likely to have engaged in unprotected anal intercourse with casual partners (p.001). A third of those men who broke their agreements did not inform their partner. A substantial proportion of gay men with agreements with their regular partners report some discomfort discussing sexuality and HIV serostatus with their partners. Difficulty discussing these issues may place these men at increased risk of breaking their agreements and may place both themselves and their partners at increased risk of infection.

Gαq-protein-coupled group I metabotropic glutamate receptors (mGluRs) are densely expressed in brain neurons and are actively involved in various cellular activities. In this study, we investigated the role of group I mGluRs in regulating the c-Jun N-terminal kinase (JNK)/stress-activated protein kinase in cultured neurons. We found that selective activation of mGluR5 induced a rapid and transient phosphorylation of JNK. In a series of studies to determine the mechanisms, we found that the conventional mGluR5-associated signaling pathways (inositol-1,4,5-triphosphate-mediated Ca2+release and activation of protein kinase C) were not involved in the mGluR5 regulation. Instead, ligand stimulation of mGluR5 caused a dynamic transactivation of the epidermal growth factor (EGF) receptor, which in turn triggered a downstream signaling pathway to upregulate JNK phosphorylation. Furthermore, the mGluR5-dependent JNK activation specifically activated c-Jun, but not activating transcription factor-2 or JunD, and increased activator protein-1 (AP-1)-mediated endogenous transcriptional activity. Together, we identified a novel mGluR5-to-nucleus communication through the EGF/JNK pathway, which functions to regulate AP-1-mediated transcription.

The regulation of protein phosphorylation requires coordinated interaction between protein kinases and protein phosphatases (PPs). Recent evidence has shown that the Galphaq-protein-coupled metabotropic glutamate receptor (mGluR) 5 up-regulates phosphorylation of MAPK/ERK1/2. However, signaling mechanisms linking mGluR5 to ERK are poorly understood. In this study, roles of a major serine/threonine PP, PP2A, in this event were evaluated in cultured neurons. We found that the PP1/2A inhibitors okadaic acid and calyculin A mimicked the effect of the mGluR5 agonists (RS)-3,5-dihydroxyphenylglycine and (RS)-2-chloro-5-hydroxyphenylglycine in facilitating phosphorylation of ERK1/2 and its upstream kinase, MEK1/2, in a PP2A-dependent but not PP1-dependent manner. Co-administration of either inhibitor with an mGluR5 agonist produced additive phosphorylation of ERK1/2. Enzymatic assays showed a basal level of phosphatase activity of PP2A under normal conditions, and activation of mGluR5 selectively inhibited PP2A, but not PP1, activity. In addition, a physical association of the cytoplasmic C terminus of mGluR5 with PP2A was observed, and ligand activation of mGluR5 reduced mGluR5-PP2A binding. Additional mechanistic studies revealed that mGluR5 activation increased tyrosine (Tyr307) phosphorylation of PP2A, which was dependent on activation of a p60c-Src family tyrosine kinase, but not the epidermal growth factor receptor tyrosine kinase and resulted in dissociation of PP2A from mGluR5 and reduced PP2A activity. Together, we have identified a novel, mGluR5-triggered signaling mechanism involving use- and Src-dependent inactivation of PP2A, which contributes to mGluR5 activation of MEK1/2 and ERK1/2.

This study aimed to determine and describe HIV-negative gay men's willingness to participate in HIV vaccine trials. Data were from participants who completed face-to-face interviews during the first 18 months (to the end of 2002) of recruitment into the Health in Men cohort of HIV-negative gay men in Sydney. A key outcome measure was a scale of Willingness to Participate in HIV Vaccine Trials, with scores ranging from 1 (unwilling) to 4 (willing). The 903 participants ranged in age from 18 to 75years (median=36). Mean of Willingness to Participate in HIV Vaccine Trials was 2.53 (standard deviation=0.54), with approximately 51% of the men having a score greater than the midpoint of 2.50. A reduced linear regression model yielded four significant independent associations with Willingness to Participate in HIV Vaccine Trials: lack of tertiary education ( P

Group I metabotropic glutamate receptors (mGluRs) increase cellular levels of inositol-1,4,5-triphosphate (IP3) and thereby trigger intracellular Ca2+release. Also, group I mGluRs are organized with members of Homer scaffold proteins into multiprotein complexes involved in postreceptor signaling. In this study, we investigated the relative importance of the IP3/Ca2+signaling and novel Homer proteins in group I mGluR-mediated activation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) in cultured rat striatal neurons. We found that selective activation of mGluR5, but not mGluR1, increased ERK1/2 phosphorylation. Whereas the IP3/Ca2+cascade transmits a small portion of signals from mGluR5 to ERK1/2, the member of Homer family Homer1b/c forms a central signaling pathway linking mGluR5 to ERK1/2 in a Ca2+-independent manner. This was demonstrated by the findings that the mGluR5-mediated ERK1/2 phosphorylation was mostly reduced by a cell-permeable Tat-fusion peptide that selectively disrupted the interaction of mGluR5 with the Homer1b/c and by small interfering RNAs that selectively knocked down cellular levels of Homer1b/c proteins. Furthermore, ERK1/2, when only coactivated by both IP3/Ca2+- and Homer1b/c-dependent pathways, showed the ability to phosphorylate two transcription factors, Elk-1 and cAMP response element-binding protein, and thereby facilitated c-Fos expression. Together, we have identified two coordinated signaling pathways (a conventional IP3/Ca2+vs a novel Homer pathway) that differentially mediate the mGluR5-ERK coupling in neurons. Both the Ca2+-dependent and -independent pathways are corequired to activate ERK1/2 to a level sufficient to achieve the mGluR5-dependent synapse-to-nucleus communication imperative for the transcriptional regulation.

The objective of the paper was to compare encounters involving unprotected anal intercourse (UAI) and protected anal intercourse (PAI) among HIV-negative gay men in Sydney. Data were from those completing baseline face-to-face interviews to end June 2003 for the Health in Men open cohort of HIV-negative gay men in Sydney. The 1,148 participants ranged in age from 18 to 75 years (median = 36). Three hundred and fifty-two (30.7%) reported an occasion of UAI with a casual partner in the previous 6 months and 531 (46.3%) reported an occasion of UAI with a regular partner in that same time. The men's most recent sexual contact with a casual partner involving UAI was distinguished from those involving PAI by a greater likelihood for both partners to disclose HIV serostatus (p = 0.006) and by respondents being more inclined to restrict themselves to the insertive position or to practise withdrawal during occasions involving any UAI than when a condom was used (p = 0.003 and p = 0.001 respectively). Neither location nor recreational drug use differentiated men's most recent sexual contacts involving UAI from those involving PAI. The decision by HIV-negative gay men to use condoms during sexual encounters with either regular or casual partners is guided more by HIV serostatus and risk reduction strategies than by other factors.

Increasing evidence suggests an active participation of nociceptinergic transmission in the central control of cardiovascular activity and reflex. In this study, the role of the classic opioid mu receptor and the nociceptin/orphanin FQ receptor, a novel opioid receptor, in the nucleus tractus solitarii (NTS) in the regulation of cardiovascular activity was investigated and compared in chronically cannulated and freely moving conscious rats. Microinjections of nociceptin, an endogenous ligand for the nociceptin receptor, into the relatively rostral NTS produced dose-related (0.04, 0.2, and 1 nmol) increases in blood pressure and heart rate. Intra-NTS injection of the selective nociceptin receptor antagonist [Nphe(1)]Nociceptin(1-13)NH(2) (NOR-AN) at 1 nmol blocked the increases in blood pressure and heart rate induced by nociceptin. In contrast, pretreatment with the nonselective opioid receptor antagonist naloxone (5 nmol) had no effects on the cardiovascular responses to nociceptin. Like nociceptin, microinjection of endomorphin-1 (EM-1), an endogenous ligand for the opioid mu receptor, into the rostral NTS increased blood pressure and heart rate in a dose-dependent manner (0.04, 0.2, and 1 nmol). Pretreatment with naloxone (5 nmol), but not NOR-AN, blocked cardiovascular responses elicited by EM-1. Neither NOR-AN nor naloxone alone had significant effects on the baseline blood pressure and heart rate. Injection of excitatory amino acid l-glutamate (1 nmol) into the same sites caused the typical depressor and bradycardic responses. In the caudal NTS areas, nociceptin and EM-1 seemed to induce opposite responses: hypotension and bradycardia. These results suggest that the novel nociceptin receptors and traditional opioid receptors in the NTS may be independently involved in the regulation of cardiovascular activity.

Activation of group I metabotropic glutamate receptors (mGluRs) up-regulates transcription factor cyclic AMP response element-binding protein (CREB) and Elk-1 phosphorylation via extracellular signal-regulated kinase 1/2 (ERK1/2) in the striatum in vivo. Protein phosphatase 1/2A further regulates immediate early gene expression by inactivating (dephosphorylating) CREB. In this study, using semi-quantitative immunohistochemical and western blot analyses and in situ hybridization histochemistry, we found that intrastriatal infusion of the protein phosphatase 1/2A inhibitor okadaic acid (0.005, 0.05 and 0.5 nmol) increased CREB and Elk-1 phosphorylation and c-Fos immunoreactivity in the injected dorsal striatum in a dose-dependent manner. In addition, okadaic acid (0.05 and 0.5 nM) increased c-fos mRNA expression in the dorsal striatum in a dose-dependent manner. Intrastriatal infusion of the group I agonist 3,5-dihydroxyphenylglycine (DHPG) at 100 and 250 nM also increased CREB and Elk-1 phosphorylation. Pre-treatment of okadaic acid (0.05 nm) did not alter DHPG-induced increases in the phosphorylation of the two transcription factors. These data suggest that protein phosphatase 1/2A in striatal neurons is tonically active in dephosphorylating CREB and Elk-1 and thus suppressing constitutive c-fos mRNA and protein expression. Inhibition of the phosphatase 1/2A may contribute to the group I mGluR-regulated phosphorylation of these transcription factors and c-fos expression.

Against a background of increasing unprotected anal intercourse (UAI) in the Sydney gay community (and internationally), complementary cross-sectional surveys of sexual practice were conducted among gay men of Asian background in 1999 (N = 319) and 2002 (N = 457). Self-complete questionnaires were used with recruitment at gay bars, gay social functions, and gay sex-on-premises venues. In 2002, self-report HIV status was 73.7% HIV-negative, 3.6% HIV-positive, and 22.8% unknown status (no significant change from 1999). Over time, the proportion of gay Asian men who reported any UAI with regular partners (in the previous 6 months) did not change significantly: 27.9% in 1999; 24.3% in 2002. Similarly, rates of any UAI with casual partners remained steady: 16.3% in 1999; 14.4% in 2002. Only one factor, more extensive engagement in esoteric practices (fisting, sadomasochism, group sex, rimming), was independently associated with sexual risk practice. This suggests that risk in this population of gay men, as in others, has more to do with the sexual cultures in which men are embedded rather than individual-level differences.

N-methyl-D-aspartate (NMDA) receptors are heteromeric assemblies of subunits (NR1 and NR2A–D), and are enriched in the striatum. Receptor phosphorylation has recently been demonstrated on the NR1 subunit at three serine residues, 897, 896, and 890, which appear to correspond to the level of receptor activity. In this study, expression of phospho-specific NR1 subunits at serine 897 (pNR1S897), serine 896 (pNR1S896), or serine 890 (pNR1S890) in neurochemically identified neurons of the adult rat striatum was detected by using double-immunofluorescent labeling or combined in situ hybridization and immunohistochemistry. In both the dorsal and ventral striatum, pNR1S897 was expressed at high levels in projection neurons containing >55% dynorphin (striatonigral) and >90% enkephalin (striatopallidal) and in interneurons that were 100% positive for choline, >90% positive for parvalbumin, and >45% positive for somatostatin (co-containing neuropeptide Y and neuronal nitric oxide synthase). Low levels of pNR1S896 were present in a small portion of projection neurons (

The Galphaq protein-coupled metabotropic glutamate receptor subtype-5 (mGluR5) is densely expressed in medium spiny projection neurons of striatum. Emerging evidence suggests a significant role of mGluR5 in the addictive plasticity of striatal neurons that is likely derived from inducible cellular gene expression related to stimulation of mGluR5 and associative signaling proteins. In this study, we found that activation of mGluR5 with a selective agonist (RS)-2-chloro-5-hydroxy-phenylglycine (CHPG) induced a rapid and transient phosphorylation of a transcription regulator Elk-1 in cultured striatal neurons from rat E19 embryos or neonatal day-1 pups. The Elk-1 phosphorylation was dose-dependent and occurred in neurochemically identified GABAergic neurons, but not glia. A series of experiments further demonstrated that the CHPG-stimulated Elk-1 phosphorylation was mediated through selective activation of mGluR5-regulated phospholipase C and associative second messenger system, i.e. 1,4,5,-triphosphate-sensitive Ca2+ release. Moreover, the Elk-1 phosphorylation was partially dependent on mGluR5-mediated co-activation of NMDA, but not kainate/AMPA receptors and L-type voltage-operated Ca2+ channels. Using an immediate early gene c-fos as a report of inducible gene expression, we found that CHPG induced marked c-fos mRNA expression. The c-fos induction kinetically corresponded to the Elk-1 phosphorylation and was attenuated by antisense oligonucleotides that selectively knocked down Elk-1 proteins. These results indicate that glutamatergic tone on mGluR5 is positively coupled to Elk-1 phosphorylation in striatal neurons via multiple signaling mechanisms involving Ca2+ release and NMDA activation, and the mGluR5-mediated Elk-1 phosphorylation facilitates gene transcription.

Metabotropic glutamate receptors (mGluRs) are G-protein-coupled receptors and are densely expressed in medium spiny projection neurons of striatum. Emerging evidence demonstrates a significant role of mGluRs in the regulation of striatal functions. Activation of mGluRs alters local transmitter release and behaviors of experimental animals. In particular, mGluRs regulate phosphorylation of several key signaling proteins (protein kinases and transcription factors) resulting in significant changes in immediate early gene and neuropeptide gene expression in striatal neurons. The prominent involvement of mGluRs in genomic responses to synaptic stimulation is considered to play a pivotal role in the development of synaptic/neuronal plasticity underlying long-term adaptive changes in cellular physiology related to a variety of neurologic disorders. Available data indicate that the eight subtypes of mGluRs have distinct effects on gene expression. The group I subtypes (mGluR1/5) facilitate, whereas group II (mGluR2/3) and III (mGluR4/6/7/8) subtypes inhibit, gene expression. Due to their significance in regulating drug action, mGluRs have been considered as promising targets for the development of novel therapeutic drugs for the treatment of drug addiction. The present review summarizes the roles of mGluRs in the regulation of behavior, transmitter release and particularly genomic responses in striatal neurons to dopamine stimulation, following a description of anatomical organization of mGluRs in the striatum. The possible pre- and postsynaptic mechanisms that process mGluR modulatory effects are also discussed in detail. Finally, potential of mGluRs as targets for the development of therapeutic drugs for addictive and other mental illnesses concludes this review.

Group I metabotropic glutamate receptors (mGluRs) are positively coupled to phospholipase C (PLC) via G α q -proteins and are expressed in the medium-sized projection neurons of striatum. To characterize the group I mGluR/PLC-sensitive modulation of intracellular Ca 2 + ([Ca 2 + ] i ) signalling, primary neuronal cultures were prepared from the striatum of E19 rat embryos or neonatal day-1 rat pups. Cytoplasmic Ca 2 + signals were examined with fura-2/AM at a signal cell level. After 17-18 days in culture, a profound Ca 2 + response consisting of two phases was induced in cultured striatal neurons following bath application of the selective group I agonist, 3,5-dihydroxyphenylglycine (DHPG). The [Ca 2 + ] i elevation was concentration- and time-dependent, and was blocked by coexposure to the group I antagonist, Ν-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC), or the PLC inhibitor, U-73122, but not to the group II/III antagonist (RS)-α-methylserine-Ophosphate monophenyl ester (MSOPPE). A series of further pharmacological studies demonstrated that the initial spike-like transient was dependent on intracellular Ca 2 + mobilization through 1,4,5-triphosphate-sensitive stores, and the second long-lasting rise was dependent on extracellular Ca 2 + influx through N-methyl-D-aspartate (NMDA) receptors and especially L-type voltage-operated Ca 2 + channels. Lastly, using an immediate early gene c-fos as a report of inducible gene expression, the resultant [Ca 2 + ] i elevation contributes to DHPG-stimulated c-fos mRNA and Fos protein expression in striatal neurons as revealed by quantitative in situ hybridization and immunocytochemistry, respectively. These results demonstrate that group I mGluRs are able to affect Ca 2 + homeostasis at multiple levels and trigger Ca 2 + -sensitive gene transcription in striatal neurons.

The metabotropic glutamate receptor subtype 5 (mGluR5) is densely expressed in striatal projection neurons. As a G protein-coupled receptor, mGluR5 may initiate an intracellular cascade that conveys extracellular signals to gene expression. This study investigated the possible role of mGluR5 in the inducible phosphorylation of a nuclear transcription factor, cAMP response element-binding protein (CREB), in primary cultures of striatal neurons from rat E19 embryos or neonatal day-1 pups. We found that selective activation of mGluR5 with a selective agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG) induced a rapid and transient increase in phosphorylated CREB immunoreactivity in striatal neurons as analyzed by both immunocytochemistry and western blot. The increase in CREB phosphorylation was concentration-dependent, and seen in neurochemically identified GABAergic neurons. Pre-treatment with the mGluR5 antagonist 2-methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP) blocked the CHPG phosphorylation of CREB. In contrast, the mGluR1 antagonist, 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOet) did not alter CHPG-stimulated CREB phosphorylation. The mGluR5 antisense oligonucleotides, but not their controls, selectively reduced basal mGluR5 levels as well as CREB phosphorylation in response to CHPG addition. Lastly, using an immediate early gene c-fos as a reporter of inducible gene expression downstream to phosphorylated CREB, we found that CHPG induced a rapid and transient increase in c-fos mRNA levels in cultured neurons as revealed by quantitative in situ hybridization. The increase in c-fos was kinetically correlated well with the CREB phosphorylation and blocked by MPEP and the CREB antisense oligonucleotides. These results demonstrate a positive linkage from surface mGluR5 to CREB phosphorylation, which is able to facilitate immediate gene expression in striatal neurons.

Objectives: We quantified concomitant medication polypharmacy, pharmacokinetic and pharmacodynamic interactions, adverse effects and adherence in Australian adults on effective antiretroviral therapy. Design: Cross-sectional. Methods: Patients recruited into a nationwide cohort and assessed for prevalence and type of concomitant medication (including polypharmacy, defined as ≥5 concomitant medications), pharmacokinetic or pharmacodynamic interactions, potential concomitant medication adverse effects and concomitant medication adherence. Factors associated with concomitant medication polypharmacy and with imperfect adherence were identified using multivariable logistic regression. Results: Of 522 participants, 392 (75%) took a concomitant medication (mostly cardiovascular, nonprescription or antidepressant). Overall, 280 participants (54%) had polypharmacy of concomitant medications and/or a drug interaction or contraindication. Polypharmacy was present in 122 (23%) and independently associated with clinical trial participation, renal impairment, major comorbidity, hospital/general practice-based HIV care (versus sexual health clinic) and benzodiazepine use. Seventeen participants (3%) took at least one concomitant medication contraindicated with their antiretroviral therapy, and 237 (45%) had at least one pharmacokinetic/pharmacodynamic interaction. Concomitant medication use was significantly associated with sleep disturbance and myalgia, and polypharmacy of concomitant medications with diarrhoea, fatigue, myalgia and peripheral neuropathy. Sixty participants (12%) reported imperfect concomitant medication adherence, independently associated with requiring financial support, foregoing necessities for financial reasons, good/very good self-reported general health and at least 1 bed day for illness in the previous 12 months. Conclusion: In a resource-rich setting with universal healthcare access, the majority of this sample took a concomitant medication. Over half had at least one of concomitant medication polypharmacy, pharmacokinetic or pharmacodynamic interaction. Concomitant medication use was associated with several adverse clinical outcomes.

Background Routine HIV clinical monitoring is vital for people living with HIV (PLHIV) after treatment initiation. The relationship between clinical visits during the first 6 months after initial antiretroviral therapy (ART) and long-term, HIV-related mortality and service retention was investigated. Methods: A retrospective ART observational research database was established based on de-identified data extracted from 6959 records of adult HIV-positive registrants held by Hunan CDC (Center for Disease Control and Prevention) between 2003 and 2013. Results: During the first 6 months of initiation into ART, 2364 (34.0%) of PLHIV had completed four scheduled visits, meeting the Chinese ART clinical monitoring standards. From 6 months onwards (up to 36 months), this group had the lowest HIV-related mortality (4.4%) compared with those who had more or less than four kept visits in the first 6 months [one visit only: adjusted hazards ratio (AHR) = 3.15, 95% CI 2.24–3.88; two visits: AHR = 2.24, 95% CI 1.80–3.01; three visits: AHR = 1.86, 95% CI 1.69–2.05; and >4 visits: AHR = 1.37, 95% CI 1.11–1.72]. Those with less than three kept visits were also at increased risk of cohort loss to follow up (ART discontinuation, prolonged service disengagement or death). A myriad of personal, clinical and social factors are identified to be associated with increased HIV-related mortality and clinical retention. Conclusions: Enabling PLHIV to complete four scheduled clinical visits during the first 6 months of ART initiation, as recommended by the Chinese CDC, is critical.

Female sex workers are a priority population for HIV prevention and health promotion in China. This paper examines the patterns of and factors associated with the utilisation of HIV-related and general health services by establishment-based sex workers in Hongkou District, Shanghai. Participants were recruited through a three-stage sampling strategy and invited to self-complete a brief survey in 2012. The median age of the 400 participants included in the analyses was 33 years (range = 18-52 years old), with over three-quarters being married at the time of the survey. Participants were mostly internal migrants, more than half had lived in Shanghai for six months or longer and nearly two-thirds were working in an establishment with a total of less than five female sex workers. Routine physical examination and HIV testing were the most commonly accessed health services in the previous 12 months. Altogether, 347 women (86.8%) had actively sought, including 157 women had obtained, free health services mainly from local Community Health Service Centres (CHSCs) in the previous 12 months. The active seeking of free, largely CHSC-provided health services was associated with a longer duration of residence in Shanghai (adjusted odds ratio [AOR] = 2.55, 95% CI = 1.32-4.93; p < 0.01) and having tested for HIV in the previous 12 months (AOR = 3.68, 95% CI = 1.84-7.38; p < 0.001). Conversely, a higher annual income (AOR = 0.41, 95% CI = 0.21-0.80; p < 0.01), working in a larger establishment (AOR = 0.40, 95% CI = 0.20-0.79; p < 0.01) and knowing that HIV can be transmitted through blood transfusion with unscreened blood (AOR = 0.21, 95% CI = 0.05-0.91; p < 0.05) were associated with not actively seeking such services. Free, community-based health services are highly demanded by establishment-based female sex workers in Shanghai. Scaling-up of free and integrated health services provided by community-based health service providers in metropolitan areas in China and beyond holds promise for promoting health and well-being of female sex workers.

Objective: To examine the validity and impact of record linkage using name code compared to full name records. Methods: A registry of 45,419 opioid substitution clients (1985–2007) was linked with national population-based death and cancer registries using registrant's name, date of birth, sex, state, postcode and date of death. Records were linked using full name and then using the first two letters of the given and surname (2×2 name code). Sensitivity and specificity were computed and regression analysis used to identify factors related to linkage accuracy. Standardised mortality ratios (SMR) and standardised cancer incidence ratios (SIR) were estimated. Results: The sensitivity and specificity of name code compared to full name linkage were 65.31% and 99.91% for death records and 76.81% and 99.89% for cancer records. Registrants' age and sex and accuracy of the registries were associated with risk of false linkages. Death and cancer risks (SMR 6.98, 95%CI 6.77–7.19; SIR 1.16, 95%CI 1.08–1.24) were significantly under-estimated using name code linkage (SMR 4.39, 95%CI 4.23–4.56; SIR 0.92, 95%CI 0.85–0.99). Conclusion: Record linkage using 2×2 name code has low sensitivity but high specificity, resulting in conservative estimates of death and cancer risk. This may translate to meaningful differences in outcomes.

Emerging evidence indicates that group I metabotropic glutamate receptors (mGluRs) play a significant role in the addictive plasticity of striatal neurons. The plasticity is probably mediated by altered cellular gene expression in relation to stimulation of group I mGluRs and associative signaling proteins. In this study, we investigated the signaling linkage of surface group I mGluRs to the nuclear transcription factor cAMP response element-binding protein (CREB) in cultured primary striatal neurons. We found that selective activation of group I mGluRs (primarily the mGluR5 subtype) was able to up-regulate CREB phosphorylation in neurochemically identified gamma-aminobutyratergic neurons but not glia. The CREB phosphorylation was independent of kainate/AMPA receptors but partially dependent of concomitant NMDA receptor activation. Because L-type voltage-operated Ca(2+) channel inhibitors substantially blocked the CREB phosphorylation, group I receptors are believed to lead to activation of L-type Ca(2+) channels, resulting in the CREB phosphorylation. Indeed, further studies on signaling pathways showed that group I mGluRs, by activating phospholipase C, induced a rapid and transient Ca(2+) release from the 1,4,5-triphosphate-sensitive rather than ryanodine-sensitive Ca(2+) store. The transient Ca(2+) rise in turn triggered the opening of L-type Ca(2+) channels, resulting in a progressively larger increase in cytoplasmic Ca(2+) levels that is responsible for subsequent CREB phosphorylation. These results indicate that Ca(2+)-coupled group I mGluRs possess the ability to up-regulate CREB phosphorylation via the intracellular Ca(2+) release-induced activation of L-type Ca(2+) channels and, to a lesser extent, NMDA receptors in primary striatal neurons.

The construct of individualism-collectivism was used to examine how gay Asian men in Sydney deal with dual gay and Asian identities. Nineteen participants, most of East and South-East Asian background, participated in three focus groups. The results suggested that these gay Asian men often faced problems in dealing with being both gay and Asian in a dominant, White, heterosexual society. Much conflict was related to differences between group-oriented Asian cultures and individual-oriented Western culture. To deal with the divide, it is argued that stronger ties could be developed between gay communities and individuals on the basis of mutual understanding and appreciation of the cultural differences.

Malignant oral ulcers are common pathological occurrence in oral and maxillofacial tumors. A noninvasive method for diagnosis of malignant oral ulcers was developed in the study, which is based on hematoporphyrin monomethylether (HMME) fluorescence spectroscopy. The objective of this work is to determine the feasibility of this method in differentiating the malignant tissues from the inflammatory ones in the hamster cheek pouch model. Adult hamsters were used for the study and a cheek pouch model was established. For the malignant model, the 9, 10-dimethyl-1, 2-benzanthracene carcinogenesis was applied to one cheek pouch for 10 weeks (N = 35). The simple ulcers were created on buccal cheek mucosa in a simple manner (N = 10). Prior to sacrifice, HMME solution was injected into the tissues. The induced fluorescence spectra of the cheek tissues were recorded by a fiber spectrometer with excitation at 405 nm. A spectral algorithm was used to eliminate the effect of autofluorescence, and a spectral parameter S was selected as diagnostic criterion. After fluorescence measurement, the animals were sacrificed and the measured tissues were collected. Histological staining was performed and the results of histopathological evaluation were documented. The diagnostic criteria that reflected the fluorescence intensity were set as follows: normal, S ≤ 10; simple ulcer, 230 ≤ S ≤ 290; and malignant ulcer, 140 ≤ S ≤ 200. The sensitivity and specificity of this detection method was verified by scalpel biopsy, and the overall accuracy was over 90 %. The results of this study showed that the fluorescence spectroscopic method implemented by HMME can accurately differentiate the two kinds of clinically indistinguishable diseases.

Increasing evidence supports the critical role of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors in psychostimulant action. These receptors are regulated via a phosphorylation-dependent mechanism in their trafficking, distribution, and function. The hippocampus is a brain structure important for learning and memory and is emerging as a critical site for processing psychostimulant effects. To determine whether the hippocampal pool of AMPA receptors is regulated by stimulants, we investigated and characterized the impact of amphetamine (AMPH) on phosphorylation of AMPA receptors in the adult rat hippocampus in vivo. We found that AMPH markedly increased phosphorylation of AMPA receptor GluA1 subunits at serine 845 (S845) in the hippocampus. The effect of AMPH was dose dependent. A single dose of AMPH induced a rapid and transient increase in S845 phosphorylation. Among different hippocampal subfields, AMPH primarily elevated S845 phosphorylation in the Cornu Ammonis area 1 and dentate gyrus. In contrast to S845, serine 831 phosphorylation of GluA1 and serine 880 phosphorylation of GluA2 were not altered by AMPH. In addition, surface expression of hippocampal GluA1 was up-regulated, while the amount of intracellular GluA1 fraction was concurrently reduced in response to AMPH. GluA2 protein levels in either the surface or intracellular pool were insensitive to AMPH. These data demonstrate that the AMPA receptor in the hippocampus is sensitive to dopamine stimulation. Acute AMPH administration induces dose-, time-, site-, and subunit-dependent phosphorylation of AMPA receptors and facilitates surface trafficking of GluA1 AMPA receptors in hippocampal neurons in vivo. Acute injection of amphetamine increased phosphorylation of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluA1 subunits at a protein kinase A (PKA)-sensitive site (S845) in the rat hippocampus. This increase was dose- and time-dependent and correlated with an increase in surface GluA1 expression. Thus, amphetamine can upregulate GluA1 phosphorylation and surface trafficking of GluA1 in hippocampal neurons in vivo.

Objectives With the increasing momentum to maximize the benefits of antiretroviral therapy (ART), better understanding of opportunities and challenges in increasing ART coverage and promoting early ART initiation is urgently needed. Key sociodemographic, clinical and behavioural factors associated with Australian HIV-positive gay men's current nonuse of ART were systematically examined. Methods Data were based on 1911 responses from HIV-positive men who had participated in the Australian Gay Community Periodic Surveys (GCPS) between 2010 and 2012. Stratified univariate analysis and multivariate logistic regression were used. Results A majority of the participants were recruited from gay community venues and events and self-identified as gay or homosexual. On average, they were 44 years old and had been living with HIV for at least 10 years. Close to 80% (n = 1555) were taking ART, with >90% further reporting an undetectable viral load at the time of the survey. From 2010 to 2012, there had been a moderate increase in ART uptake [adjusted odds ratio (AOR) 1.40; 95% confidence interval (CI) 1.20–1.65]. In addition, younger age (AOR 1.66; 95% CI 1.45–1.92), recent HIV diagnosis (AOR 1.78; 95% CI 1.59–1.98), not receiving any social welfare payments (AOR 2.20; 95% CI 1.05–2.54) and no annual screening for sexually transmissible infections (AOR 1.55; 95% CI 1.03–2.34) were independently associated with ART nonuse. Conclusions Current ART coverage among HIV-positive gay men in Australia is reasonably high. To further increase ART coverage and promote early ART initiation in this population, better clinical care and sustained structural support are needed for HIV management throughout their life course.

Neural progenitor cells are present in the rodent brain throughout adulthood, and can proliferate and differentiate into new neurons and/or glia to repair injury. To explore the repair processes mediated by brain progenitor cells, a selective lesion of the nigrostriatal dopaminergic pathway was induced in young adult mice by repeated administration of the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). A thymidine analog, bromodeoxyuridine (BrdU), was used as a tracer for DNA synthesis to label the dividing cells and their terminal progeny following injury. Three days after MPTP treatments (25 mg/kg, once daily for 5 days), an 8-fold increase in the number of BrdU-labeled newborn cells was observed in the dorsal striatum. A 5-fold increase was also seen in the substantia nigra (SN). Newborn cells in the striatum survived beyond 60 days after their birth whereas newborn cells in the SN survived for less than 31 days. The vast majority of newborn cells in the striatum differentiated into astroglia according to their radial morphology and co-expression with an astroglial marker, S100β, within 10 days after birth. In contrast, most BrdU-positive cells in the SN failed to co-express S100β. Little or none of BrdU-labeled cells in both the striatum and SN were found to co-localize with a neuronal marker, neuronal nuclear antigen, or tyrosine hydroxylase during the full course of survival days surveyed (3 to 60 days). Repeated MPTP also decreased dopamine content and uptake in the striatum, which showed a significant recovery 31 days after MPTP lesion. These results demonstrate a rapid and profound astrogenesis in the striatum of young adult mice in response to toxic dopaminergic insult. The lack of neurogenesis in the two affected brain areas indicates the relative importance of glial cell regeneration in repairing MPTP injury.

Metabotropic glutamate receptor 1 (mGluR1) is a G-protein-coupled receptor and is expressed in the medium spiny projection neurons of mouse striatum. To define the role of mGluR1 in actions of psychostimulant, we compared both motor behavior and striatal neuropeptide mRNA expression between mGluR1 mutant and wild-type control mice after a single injection of amphetamine. We found that acute amphetamine injection increased motor activity in both mutant and control mice in a dose-dependent manner (1, 4, and 12 mg/kg, i.p.). However, the overall motor responses of mGluR1 −/− mice to all three doses of amphetamine were significantly greater than those of wild-type +/+ mice. Amphetamine also induced a dose-dependent elevation of preprodynorphin mRNA in the dorsal and ventral striatum of mutant and wild-type mice as revealed by quantitative in situ hybridization. In contrast to behavioral responses, the induction of dynorphin mRNA in both the dorsal and ventral striatum of mutant mice was significantly less than that of wild-type mice in response to the two higher doses of amphetamine. In addition, amphetamine elevated basal levels of substance P mRNA in the dorsal and ventral striatum of mGluR1 mutant mice to a similar level as that of wild-type mice. There were no differences in basal levels and distribution patterns of the two mRNAs between the two genotypes of mice treated with saline. These results demonstrate a clear augmented behavioral response of mGluR1 knockout mice to acute amphetamine exposure that is closely correlated with reduced dynorphin mRNA induction in the same mice. It appears that an intact mGluR1 is specifically critical for full dynorphin induction, and impaired mobilization of inhibitory dynorphin system as a result of lacking mGluR1 may contribute to an augmentation of motor stimulation in response to acute administration of psychostimulant.

Altered glutamatergic transmission in the striatum may be implicated in behavioral sensitization to repeated amphetamine (AMPH) administration. Quantitative in situ hybridization histochemistry was performed to define the effects of acute and chronic AMPH exposures on mRNA expression of Group I metabotropic glutamate receptors (mGluRs) in the striatum. Behavioral ratings indicated that the motor activity of rats was significantly higher after the final of five daily AMPH injections (4 mg/kg, i.p.) than that after the first of five daily AMPH, indicative of the development of behavioral sensitization. Moreover, the motor activity of rats treated with five daily AMPH was significantly greater than that of rats treated with five daily saline in response to a 2 mg/kg challenge dose of AMPH 7, 14, 28, and 60 days after the discontinuation of drug treatments, indicative of the persistent expression of behavioral sensitization. Three hours after acute administration of AMPH to naive rats, mGluR1 and mGluR5 mRNA expression in the dorsal (caudatoputamen) and ventral (nucleus accumbens) striatum showed no change as compared to acute saline injection. In rats that developed behavioral sensitization to repeated AMPH, mGluR1 levels in the dorsal and ventral striatum were increased by 53% and 43%, respectively, 3 h after the final AMPH treatment. However, this change did not persist during withdrawal since it was not observed 7, 14, and 28 days after the discontinuation of AMPH treatment. Conversely, mGluR5 levels were markedly reduced 3 h after the final of five daily AMPH treatments in the entire striatum of sensitized rats (34% and 77% of controls in the dorsal and ventral striatum, respectively). The reduction persisted at 7, 14, and 28 days of withdrawal. These results reveal a close linkage between striatal Group I mGluR gene expression and behavioral sensitization to AMPH. This may indicate functional implications of the two subtypes of Group I mGluRs in the regulation of behavioral sensitization to the dopamine stimulant.

G protein-coupled receptors (GPCRs) are subject to the regulation by protein kinases. By controlling the phosphorylation-dephosphorylation balance, protein kinases actively modify GPCR expression and function. In a recent study, we have identified a novel phosphorylation-dependent regulation of Gαi/o-coupled muscarinic acetylcholine receptors. A synapse-enriched protein kinase, Ca(2+)/calmodulin-dependent protein kinase II (CaMKIIα), binds directly and selectively to second intracellular loops of muscarinic M4 receptors (M4Rs). This Ca(2+)-sensitive binding enables CaMKIIα to phosphorylate M4Rs at a selective threonine residue. In rat striatal neurons which abundantly express M4Rs, rapid cytoplasmic Ca(2+) rises enhance the association of CaMKIIα with M4Rs and increase threonine phosphorylation of the receptor. This CaMKIIα-mediated phosphorylation results in a potentiation of M4R activity, which is critical for controlling cellular and behavioral responsivity to dopamine stimulation. In sum, our data identify a novel kinase-GPCR interaction. Through a Ca(2+)/activity-sensitive manner, CaMKIIα contributes to maintaining acetylcholine-dopamine homeostasis in the basal ganglia.

Group III metabotropic glutamate receptors (mGluRs) are negatively coupled to adenylate cyclase through G-proteins. Activation of this group of mGluRs shows an inhibition of dopaminergic transmission in the forebrain. To define the role of striatal group III mGluRs in the regulation of basal and dopamine-stimulated motor behavior, the recently developed agonist and antagonist relatively selective for group III mGluRs were utilized to pharmacologically enhance and reduce group III mGluR glutamatergic tone in the dorsal striatum of chronically cannulated rats. Bilateral injections of a group III agonist, L-2-amino-4-phosphonobutyrate (L-AP4), did not alter basal levels of motor activity at three doses surveyed (1, 10, and 100 nmol). Neither did intracaudate injection of a group III antagonist, alpha-methyl-4-phosphonophenylglycine (MPPG), at 10, 30, and 100 nmol. However, pretreatment with L-AP4 (10 and 100 nmol) dose dependently blocked hyperlocomotion induced by acute injection of cocaine (20 mg/kg, i.p.), amphetamine (2.5 mg/kg, i.p.), or apomorphine (1 mg/kg, s.c.). The behavioral activity induced by cocaine was much more sensitive to L-AP4 than that induced by amphetamine and apomorphine. At 100 nmol, L-AP4 completely blocked cocaine effect whereas amphetamine- and apomorphine-stimulated behaviors were blocked only by 28% and 31%, respectively. The blocking effect of L-AP4 on cocaine action was reversed by pretreatment with MPPG. MPPG itself did not modify behavioral responses to cocaine, amphetamine, or apomorphine. These data indicate that the glutamatergic tone on the group III mGluRs is not active in the regulation of basal and acute dopamine-stimulated motor activity. However, enhanced group III mGluR glutamatergic transmission by an exogenous ligand is capable of suppressing behavioral responses to acute exposure of dopamine stimulants.

Group I metabotropic glutamate receptors (mGluRs) are densely expressed in the medium-sized spiny projection neurons of striatum. Activation of this group of the mGluRs modifies neuronal physiology through stimulation of phosphoinositide hydrolysis and intracellular Ca(2)+ release. Unlike the ionotropic glutamate receptors that mediate rapid synaptic transmission, activation of the mGluRs produces long-lasting actions brought about by modulation of activities of intracellular effectors. In this study, the role of the group I mGluRs in the modulation of extrapyramidal motor function was examined using a group I selective agonist, 3, 5-dihydroxyphenylglycine (DHPG), in chronically cannulated rats. Bilateral injections of DHPG at a series of subtoxic doses (20, 40, 80, and 160 nmol) into the central part of the dorsal striatum produced hyperlocomotion and a unique stereotypical behavior (spontaneous and repetitive twitching movement of the head and forepaws) in a dose-dependent manner. The characteristic twitchy behavior usually commenced 30 min to 1 h, and could last as long as 10 to 12 h, after a single injection of the group I agonist. The behavioral responses to DHPG administration were markedly antagonized by intrastriatal injection of the group I antagonist PHCCC (10 nmol), but not the group II/III antagonist MSOPPE (10 nmol). Intrastriatal administration of 20 nmol dantrolene, an inhibitor of intracellular Ca(2)+ mobilization, also prevented DHPG-stimulated motor activities. However, blockade of dopamine D(1) receptors with systemic administration of SCH-23390 (0.1 mg/kg, SC) did not alter the ability of DHPG to provoke behavioral activities. These data indicate that selective activation of the DHPG-sensitive group I mGluRs in the striatum can produce long-lasting stimulation of motor activity. DHPG-induced motor stimulation involves the mobilization of intracellular Ca(2)+ stores, but appears to be independent of D(1) dopaminergic transmission.

Group I metabotropic glutamate receptors (mGluRs) are positively coupled to phosphoinositide hydrolysis through G-proteins and are densely expressed in the medium-sized spiny neurons of striatum. Activation of this group of mGluRs in the striatum produces long-lasting stimulation of behavioral activity. In this study, the role of group I mGluRs in the modulation of neuropeptide mRNA expression in striatal neurons was investigated using a Group I-selective agonist, 3,5-dihydroxyphenylglycine (DHPG) in chronically cannulated rats. Unilateral injections of DHPG into the dorsal striatum (caudoputamen) at behaviorally active doses of 20, 40, and 80 nmol elevated basal levels of preprodynorphin (PPD), substance P (SP), and preproenkephalin (PPE) mRNAs in the injected dorsal striatum as revealed by quantitative in situ hybridization. The elevation of all three mRNAs was dose-dependent and the responsiveness of opioid peptide mRNAs (PPD and PPE) to acute injection of DHPG at each dose surveyed was greater than that of SP mRNA. Induction of the mRNAs was delayed and prolonged as increases in hybridization signal became evident at 2 (SP and PPE) or 3 (PPD) h, reached a peak between 3 and 6 h, and returned to normal levels 24 h after DHPG injection. Coadministration of a Group I-selective antagonist, n-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carbo xamide (PHCCC, 10 nmol), with DHPG markedly attenuated DHPG-stimulated PPD, PPE, and, to a lesser extent, SP expression. Administration of PHCCC alone had no significant effect on basal levels of three mRNA expression in the striatum. This study provides a detailed description of the dose- and time-related alterations in striatonigral PPD/SP and striatopallidal PPE mRNA expression in response to a single injection of the Group I agonist DHPG. Data obtained demonstrate a facilitatory, dynamic regulation of constitutive expression of PPD, SP, and PPE mRNAs by local enhancement of glutamatergic tone on DHPG- and PHCCC-sensitive Group I mGluRs.