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Objectives Evidence of premature cognitive ageing amongst people living with HIV (PLHIV) remains controversial due to previous research limitations including underpowered studies, samples with suboptimal antiretroviral access, varying rate of virological control, high rate of AIDS, over‐representation of non‐community samples, and inclusion of inappropriate controls. The current study addresses these limitations, while also considering mental health and non‐HIV comorbidity burden to determine whether PLHIV showed premature cognitive ageing compared with closely comparable HIV‐negative controls. Methods This study enrolled 254 PLHIV [92% on antiretroviral therapy; 84% with HIV RNA

Adenosine A1 receptors are widely expressed in the mammalian brain. Through interacting with Gαi/o‐coupled A1 receptors, the neuromodulator adenosine modulates a variety of cellular and synaptic activities. To determine the linkage from A1 receptors to a key intracellular signaling pathway, we investigated the impact of blocking A1 receptors on a subfamily of nonreceptor tyrosine kinases, that is, the Src family kinase (SFK), in different rat brain regions in vivo. We found that pharmacological blockade of A1 receptors by a single systemic injection of the A1 selective antagonist 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPX) induced an increase in autophosphorylation of SFKs at a consensus activation site, tyrosine 416 (Y416), in the two subdivisions of the striatum, the caudate putamen and nucleus accumbens. DPCPX also increased SFK Y416 phosphorylation in the medial prefrontal cortex (mPFC) but not the hippocampus. The DPCPX‐induced Y416 phosphorylation was time dependent and reversible. In immunopurified Fyn and Src proteins from the striatum, DPCPX elevated SFK Y416 phosphorylation and tyrosine kinase activity in Fyn but not in Src proteins. In the mPFC, DPCPX enhanced Y416 phosphorylation and tyrosine kinase activity in both Fyn and Src immunoprecipitates. DPCPX had no effect on expression of total Fyn and Src proteins in the striatum, mPFC, and hippocampus. These results demonstrate a tonic inhibitory linkage from A1 receptors to SFKs in the striatum and mPFC. Blocking this inhibitory tone could significantly enhance constitutive SFK Y416 phosphorylation in the rat brain in a region‐ and time‐dependent manner., Pharmacological blockade of adenosine A1 receptors enhanced phosphorylation and enzymatic activity of the Src family kinases such as Fyn and/or Src in the adult rat brain in a region‐ and time‐dependent manner. This supports an existence of a tonic inhibitory linkage from A1 receptors to a key and Fyn/Src‐dependent intracellular signaling pathway in neurons in vivo under normal conditions.

The prognostic role of c-Met expression in patients with head and neck cancer were controversial among different studies. Thus, we performed a meta-analysis to evaluate the relationships between c-Met expression and survival and clinical parameters of head and neck cancer patients. Summary hazard ratio (HR) and 95% confidence intervals (CIs) were calculated to analyze the correlations between c-Met expression and overall survival (OS), and disease-free survival (DFS). Furthermore, odds ratios (ORs) and 95% CIs were used to describe the relationships between c-Met expression and different clinicopathological parameters. A total of 2417 patients from 19 studies were enrolled in the final analysis. The results showed that patients with higher c-Met expression had a poor OS (HR, 1.65; 95% CI, 1.20-2.27) and DFS (HR, 1.48; 95% CI, 0.99-2.20). In addition, c-Met expression was associated with the N classification of patients with head and neck cancer. These results suggested that c-Met expression was a risk factor for head and neck cancer, and increased c-Met expression would be a predictor of a poorer prognosis for the patients.

Major depressive disorder is a common form of mental illness. Many brain regions are implicated in the pathophysiology and symptomatology of depression. Among key brain areas is the striatum that controls reward and mood and is involved in the development of core depression-like behavior in animal models of depression. While molecular mechanisms in this region underlying depression-related behavior are poorly understood, the glutamatergic input to the striatum is believed to play a role. In this study, we investigated changes in metabotropic glutamate (mGlu) receptor expression and signaling in the striatum of adult rats in response to prolonged (10-12 weeks) social isolation, a pre-validated animal paradigm modeling depression in adulthood. We found that mGlu5 receptor protein levels in the striatum were increased in rats that showed typical depression- and anxiety-like behavior after chronic social isolation. This increase in mGlu5 receptor expression was seen in both subdivisions of the striatum, the nucleus accumbens and caudate putamen. At subcellular and subsynaptic levels, mGlu5 receptor expression was elevated in surface membranes at synaptic sites. In striatal neurons, the mGlu5-associated phosphoinositide signaling pathway was augmented in its efficacy after prolonged social isolation. These data indicate that the mGlu5 receptor is a sensitive substrate of depression. Adulthood social isolation leads to the up-regulation of mGlu5 receptor expression and function in striatal neurons.

Co-infection with hepatitis B (HBV) and C (HCV) is common among people living with HIV (PLHIV). This study investigates the impacts of hepatitis co-infection on antiretroviral therapy (ART) outcomes and hepatotoxicity in PLHIV. The cohort study included 1984 PLHIV. Hepatotoxicity was defined by elevated alanine aminotransferase (ALT) levels. ART outcomes were measured by CD4 cell counts, viral load, and mortality rate in patients. Among 1984 PLHIV, 184 (9.3%) were co-infected with HBV and 198 (10.0%) with HCV and 54 (2.7%) were co-infected with HBV and HCV. Of these patients, 156 (7.9%) had ALT elevation ≥ grade 1 at baseline. During the course of ART, the mortality rate and its adjusted hazard ratio (AHR) in PLHIV who were co-infected with HCV (2.6/100 person-years [py], AHR = 2.3, 95%CI 1.1-4.7) was higher than for patients with mono-infected HIV, as it was for those with an elevated ALT (4.4/100 py, AHR = 3.8, [1.7-8.2]) at baseline compared to those with normal ALT. After 6-12 months of ART, the incidence of hepatotoxicity among all the patients was 3.7/100 py. The risk of hepatotoxicity was higher in HCV co-infected (18.6/100 py, adjusted odds ratio [AOR] = 12.4, [8.1-18.2]) than HIV mono-infected patients, and for all regimens (nevirapine: 30.0/100 py, 34.2, 7.3-47.9; zidovudine/stavudine: 24.7/100 py, 22.1, 7.1-25.5; efavirenz: 14.5/100 py, 9.4, 3.5-19.2; lopinavir/ritonavir: 40.1/100 py, 52.2, 9.5-88.2) except tenofovir (4.3/100 py, 4.9, 0.8-9.5). Patients with HBV/HCV co-infected had high hepatotoxicity (10.0/100 py, 6.3, 1.2-23.3) over the same period. Patients with HCV co-infection and HBV/HCV co-infection demonstrated higher hepatotoxicity rate compared with HIV mono-infected patients in China.

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.

Fyn, a major Src family kinase (SFK) member that is densely expressed in striatal neurons, is actively involved in the regulation of cellular and synaptic activities in local neurons. This SFK member is likely regulated by dopamine signaling through a receptor mechanism involving dopamine D2 receptors (D2Rs). This study characterizes the D2R-dependent regulation of Fyn in the rat striatum in vivo. Moreover, we explore whether D2Rs regulate metabotropic glutamate receptor 5 (mGluR5) in its tyrosine phosphorylation and whether the D2R–SFK pathway modulates trafficking of mGluR5. We found that blockade of D2Rs by systemic administration of a D2R antagonist, eticlopride, substantially increased SFK phosphorylation in the striatum. This increase was a transient and reversible event. The eticlopride-induced SFK phosphorylation occurred predominantly in immunopurified Fyn but not in another SFK member, Src. Eticlopride also elevated tyrosine phosphorylation of mGluR5. In parallel, eticlopride enhanced synaptic delivery of active Fyn and mGluR5. Pretreatment with an SFK inhibitor blocked the eticlopride-induced tyrosine phosphorylation and synaptic trafficking of mGluR5. These results indicate that D2Rs inhibit SFK (mainly Fyn) phosphorylation in the striatum. D2Rs also inhibit tyrosine phosphorylation and synaptic recruitment of mGluR5 through a signaling mechanism likely involving Fyn. © 2016 Wiley Periodicals, Inc.

Objectives There is evidence that HIV-positive patients are suffering from a greater burden of morbidity as they age due to nonAIDS-related complications. To date it has been difficult to determine what part of this excess risk is due to the health effects of HIV, its treatment or to lifestyle factors common to gay and bisexual men (GBM). We calculated overall and cause-specific hospitalisation rates and risk factors for hospitalisations in HIV-negative and HIV-positive cohorts of GBM and compare these with rates in the general male population. Methods We conducted a record linkage study, linking two cohorts of HIV-negative (n = 1325) and HIV-positive (n = 557) GBM recruited in Sydney, New South Wales (NSW), Australia with the NSW hospital discharge data register. We compared rates of hospitalisation in the two cohorts and risk factors for hospitalisation using random-effects Poisson regression methods. Hospitalisation rates for each cohort were further compared with those in the general male population using indirect standardisation. Results We observed 2032 hospitalisations in the HIV-negative cohort during 13 016 person-years (PYs) [crude rate: 15.6/100PYs (95% CI: 14.9–16.3)] and 2130 hospitalisations in the HIV-positive cohort during 5571 PYs [crude rate: 38.2/100PYs (95% CI: 36.6–39.9)]. HIV-positive individuals had an increased risk of hospitalisation compared with the HIV-negative individuals [adjusted-IRR: 2.34 (95% CI: 1.91–2.86)] and the general population [SHR: 1.45 (95% CI: 1.33–1.59)]. Hospitalisation rates were lower in the HIV-negative cohort compared with the general population [SHR: 0.72 (95% CI: 0.67–0.78)]. The primary causes of hospitalisation differed between groups. Conclusions HIV-positive GBM continue to experience excess morbidity compared with HIV-negative GBM men and the general population. HIV-negative GBM had lower morbidity compared with the general male population suggesting that GBM identity does not confer excess risk.

Dopamine and acetylcholine are two principal transmitters in the striatum and are usually balanced to modulate local neural activity and to maintain striatal homeostasis. This study investigates the role of dopamine and muscarinic acetylcholine receptors in the regulation of a central signaling protein, i.e., the mitogen-activated protein kinase (MAPK). We focus on the synaptic pool of MAPKs because of the fact that these kinases reside in peripheral synaptic structures in addition to their somatic locations. We show that a systemic injection of dopamine D1 receptor (D1R) agonist SKF81297 enhances phosphorylation of extracellular signal-regulated kinases (ERKs), a prototypic subclass of MAPKs, in the adult rat striatum. Similar results were observed in another dopamine-responsive region, the medial prefrontal cortex (mPFC). The dopamine D2 receptor agonist quinpirole had no such effects. Pretreatment with a positive allosteric modulator (PAM) of muscarinic acetylcholine M4 receptors (M4Rs), VU0152100, attenuated the D1R agonist-stimulated ERK phosphorylation in the two regions, whereas the PAM itself did not alter basal ERK phosphorylation. All drug treatments had no effect on phosphorylation of c-Jun N-terminal kinases (JNKs), another MAPK subclass, in the striatum and mPFC. These results demonstrate that dopamine and acetylcholine are integrated to control synaptic ERK but not JNK activation in striatal and mPFC neurons in vivo. Activation of M4Rs exerts an inhibitory effect on the D1R-mediated upregulation of synaptic ERK phosphorylation.

Introduction and Aims International research has shown that gay, bisexual and other homosexually active men (hereafter ‘gay men’) report disproportionately higher rates of risky alcohol use and associated problems compared with heterosexual men. However, little is known about alcohol use among this population in Australia. This study aimed to examine rates of risky alcohol use among a community-based sample of gay men in Sydney and characteristics of men reporting high-risk alcohol use and adverse consequences. Design and Methods A cross-sectional survey of gay men was conducted in Sydney in August 2013 as part of the ongoing Gay Community Periodic Surveys (n = 1546 eligible respondents). The Alcohol Use Disorders Identification Test–Consumption questions were used to assess alcohol use in the previous 12 months. Results Nine percent of respondents were categorised as abstinent from alcohol, 33% as low-risk drinkers, 42% as moderate-risk drinkers and 16% as high-risk drinkers. In separate multivariate logistic regression analyses, high-risk drinking and reporting ≥4 adverse alcohol consequences were associated with younger age, being Australian-born, recruitment from licensed premises and having met men for sex at gay bars and dance parties. Fifty-eight percent of high-risk drinkers reported a desire to reduce their alcohol use. Discussion and Conclusions In this community-based sample of gay men, we found high levels of moderate- to high-risk alcohol use. The results suggest that gay men should be a priority population for health promotion campaigns and treatment services. [Lea T, Ryan D, Prestage G, Zablotska I, Mao L, de Wit J, Holt M. Alcohol use among a community-based sample of gay men: Correlates of high-risk use and implications for service provision. Drug Alcohol Rev 2015;34:349–357]

Introduction and Aims The findings of Australian drug surveys are typically not stratified by sexual orientation, despite the higher prevalence of drug use generally reported among gay and bisexual men. This paper aims to examine trends in drug use among gay and bisexual men in eastern Australia between 2004 and 2011. Design and Methods Data from the cross-sectional, ongoing Gay Community Periodic Surveys (GCPS) were used to analyse drug trends among gay and bisexual men in Sydney, Melbourne and Queensland. Between 2004 and 2011, 45 273 eligible questionnaires were completed. Results There was a downward trend in recent drug use (previous 6 months) between 2004 and 2011 from 62.2% to 57.5%. However, this trend was not found among men in Queensland, bisexual men, men aged over 40 years or HIV-positive men. Club drug use peaked in 2006 (45.1%), before steadily declining to 32.4% in 2011. There were significant reductions in use of ecstasy, methamphetamine, ketamine and cannabis, increased use of cocaine, gamma hydroxybutyrate, erectile dysfunction medications, amyl nitrite and lysergic acid diethylamide, and no change in heroin use. Recent injecting drug use fluctuated over time but experienced an overall downward trend from 5.5% in 2004 to 4.0% in 2011. Discussion and Conclusions Drug use trends among gay and bisexual men in Australia are broadly consistent with downward and upward drug trends reported in other Australian drug surveys. The risks associated with drug use in this population and high rates of use supports the ongoing role of the GCPS in monitoring drug trends among homosexually active men.

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.

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.

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.

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.

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.

Previous studies from our laboratory demonstrated an antagonistic hemodynamic interaction between ethanol and clonidine in conscious and in urethane-anesthetized rats. The present study tested the hypothesis that ethanol produces its effect by counteracting clonidine-evoked inhibition of norepinephrine (NE) release at its major site of action, the rostral ventrolateral medulla (RVLM). In vivo electrochemical measurement of real-time changes in NE level in the RVLM of urethane-anesthetized Sprague-Dawley rats was made along with blood pressure and heart rate. Clonidine (30 μg/kg, iv) produced significant decreases (p < 0.05) in NE electrochemical signal and blood pressure. Ethanol (1 g/kg, iv) administered 10 min after clonidine significantly (p < 0.05) increased NE signal and counteracted clonidine-evoked hypotension. Equal volume of saline had no effect on NE signal in the RVLM nor on the hypotensive response to clonidine. Pretreatment with the same dose of ethanol (1 g/kg) caused slight increases in RVLM NE level and in blood pressure, but did not influence the electrochemical and blood pressure responses to clonidine; clonidine (30 μg/kg) administration 10 min after ethanol resulted in significant (p < 0.05) decreases in NE signal and blood pressure. These findings suggest that: (i) ethanol counteraction of the hypotensive action of clonidine involves, at least in part, opposite effects on central pathways that use NE as a neurotransmitter; (ii) the RVLM represents a possible site for the adverse hemodynamic interaction between ethanol and clonidine; and (iii) ethanol-evoked increase in RVLM NE, which correlates with its pressor effect, is much enhanced when RVLM NE level is reduced by clonidine.