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Smokers have a higher incidence of chronic pain than non-smokers, but the neural mechanism is not yet fully understood. Nicotine is the main component of tobacco and acts as an agonist for nicotinic cholinergic receptors (nAChRs) in the nervous system. This study was approved by the IACUC of UM. The effects of chronic nicotine administration on mechanical sensitivity were studied using a rat model. The changes in the expression levels of the α7 isoform of nAChR (α7-nAChR), inflammatory cytokines TNFα and COX-2, as well as the density of neuro-immune cells (astrocytes and microglia) were measured concurrently. The results indicate that long-term nicotine administration induces hypersensitivity to mechanical stimuli, as demonstrated by a significant reduction in the pain perception threshold. In response to nicotine, the expression levels of α7-nAChR increased in the periaqueductal gray matter (PAG) and decreased in the spinal cord. Acute administration of the selective α7-nAChR agonist CDP-Choline reversed this hypersensitivity. Chronic nicotine administration led to an increase of microglial cells in the dorsal horn of the spinal cord and increased expression levels of the cytokines TNFα and COX-2. This study suggests that decreased α7-nAChR expression in the spinal cord, as a result of long-term exposure to nicotine, may be causatively linked to chronic pain. Simultaneously, the increase of neuro-immune factors in the spinal cord is also a potential factor leading to chronic pain., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Varenicline is a widely used and effective drug for smoking cessation. We previously reported that varenicline aggravates atherosclerosis in apolipoprotein E knockout (ApoE KO) mice. However, it remains unknown whether varenicline affects cardiovascular events in patients with nicotine addiction. Here, we examined the effect of varenicline on atherosclerotic plaque formation in nicotine-pretreated ApoE KO mice and oxidized low-density lipoprotein (oxLDL) uptake in nicotine-treated peritoneal macrophages. Varenicline caused significant progression of plaque formation in the whole aorta and aortic root and further accelerated the increased formation of a macrophage-rich plaque area in the aortic root in nicotine-pretreated ApoE KO mice. Varenicline (10 μM) enhanced oxLDL uptake in peritoneal macrophages. Furthermore, this treatment significantly further lowered the decreased protein levels of ATP-binding cassette (ABC) transporter without affecting the expression of scavenger receptors LOX-1 and CD36 in RAW264.7 cells treated with 100 nM nicotine. Varenicline enhanced nicotine-induced oxLDL uptake in macrophages through decreased expression of cholesterol efflux transporters ABCA1 and ABCG1 and thereby progressed atherosclerotic plaque formation. Taken together, we tentatively conclude that nicotine exposure before and/or during varenicline treatment can aggravate varenicline-increased atherosclerotic plaque formation and progression. Therefore, this enhanced risk requires special consideration when prescribing varenicline to smoker patients., (Copyright © 2019 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)

Nicotinic acetylcholine receptors (nAChRs), serotonin transporters (SERT) and dopamine transporters (DAT) represent targets for the development of novel nicotinic derivatives acting as multiligands associated with different health conditions, such as depressive, anxiety and addiction disorders. In the present work, a series of functionalized esters structurally related to acetylcholine and nicotine were synthesized and pharmacologically assayed with respect to these targets. The synthesized compounds were studied in radioligand binding assays at α4β2 nAChR, h-SERT and h-DAT. SERT experiments showed not radioligand [ 3 H]-paroxetine displacement, but rather an increase in the radioligand binding percentage at the central binding site was observed. Compound 20 showed K i values of 1.008 ± 0.230 μM for h-DAT and 0.031 ± 0.006 μM for α4β2 nAChR, and [ 3 H]-paroxetine binding of 191.50% in h-SERT displacement studies, being the only compound displaying triple affinity. Compound 21 displayed K i values of 0.113 ± 0.037 μM for α4β2 nAChR and 0.075 ± 0.009 μM for h-DAT acting as a dual ligand. Molecular docking studies on homology models of α4β2 nAChR, h-DAT and h-SERT suggested potential interactions among the compounds and agonist binding site at the α4/β2 subunit interfaces of α4β2 nAChR, central binding site of h-DAT and allosteric modulator effect in h-SERT.

Azaindoles have been accepted as important structures having various biological activities in medicinal chemistry in novel drug discovery. Various azaindole derivatives have been used commercially and newer analogues are synthesized continuously. As in literature, azaindole is a very potent moiety, its derivatives displayed a number of biological activities such as kinase inhibitors, cytotoxic agents, anti-angiogenic activity, CRTh2 receptor antagonists, melanin agonists, nicotine agonists, effectiveness in alzheimer disease, cytokinin analogs, Orai inhibitors in asthma and chemokine receptor- 2 (CCR2) antagonists. This review consists of biological activities of various azaindole analogs, reported so far, and their structure activity relations, along with future perspectives in this field., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: Varenicline doubles cessation over nicotine replacement therapy (NRT) patch for "normal," but not "slow," nicotine metabolizers, as assessed by the nicotine metabolite ratio (NMR). Metabolism-informed care (MIC) could improve outcomes by matching normal metabolizers with non-nicotine medication (e.g., varenicline) and slow metabolizers with NRT patch., Methods: We conducted a feasibility randomized controlled trial of MIC versus guideline based care (GBC) among 81 outpatient adult daily smokers with medical comorbidity. Participants reported perceptions of MIC, underwent blood draw for NMR, and received expert cessation counseling. For MIC participants, medication selection was informed by NMR result (normal (≥0.31) vs. slow (< 0.31)). The primary outcome was MIC feasibility, reflected by attitudes toward MIC and by match rates between NMR and medication. Secondary endpoints (cessation confidence, medication use, smoking status) were assessed over 6 months to inform future studies., Results: Participants were median age 53 years, 46% female, 28% black, and ~90% endorsed MIC. Despite high varenicline prescription rates (~60%) in both arms, NMR-medication matching was higher in MIC (84%) versus GBC (58%) participants (p=0.02); unadjusted odds ratio (OR) 3.67, 95% confidence interval [1.33, 11.00; p-value=0.02]. Secondary endpoints were similar at 1, 3, and 6 months., Conclusions: MIC, an NMR-based precision approach to smoking cessation, was acceptable to 90% of smokers and improved NMR-medication match rates more than 3-fold compared to GBC, even with generally high use of varenicline. These data support the feasibility of MIC, which could maximize efficacy of smoking cessation medication while minimizing side effects and cost., Implications: Among treatment-seeking daily smokers with medical comorbidity, most viewed metabolism-informed care (MIC), guided by the nicotine metabolism ratio (NMR), favorably, and were willing to accept MIC-guided medication. Compared to GBC participants (58%), more MIC participants (84%) were prescribed NMR-matched medication (i.e., normal metabolizers received varenicline; slow metabolizers received NRT patch). MIC increased the odds of optimized matching between NMR and medication more than 3-fold over GBC. Because the number needed to treat (NNT) to help one normal metabolizer quit smoking is only 4.9 for varenicline versus 26 for patch, broad implementation of MIC will improve drug efficacy in normal metabolizers as well as minimize side effects in slow metabolizers.

Animal research suggests that anhedonia is a tobacco withdrawal symptom, but this topic has not been addressed definitively in research with humans. This research sought to determine whether anhedonia is (a) an element of the tobacco withdrawal syndrome in humans and (b) an impediment to successful tobacco cessation. Data were from 1,175 smokers (58.3% women; 85.5% White) participating in a randomized double-blind, placebo-controlled trial of smoking cessation pharmacotherapies. Ecological momentary assessments for 5 days before and 10 days after the target quit day were used to assess anhedonia and other established withdrawal symptoms. Consistent with drug withdrawal, anhedonia showed an inverted-U pattern of change in response to tobacco cessation and was associated with the severity of other withdrawal symptoms and tobacco dependence. Postquit anhedonia was associated with decreased latency to relapse (hazard ratio = 1.09, 95% confidence interval [CI] [1.02, 1.17]) and with lower 8-week point-prevalence abstinence (odds ratio = .91, 95% CI [.86, .97])-relations that remained significant when other withdrawal symptoms were included as predictors. Finally, nicotine replacement therapy nearly fully suppressed the increase in abstinence-related anhedonia (β = -.66, p < .001), suggesting agonist suppression of withdrawal. Results suggest that anhedonia is a unique and motivationally significant element of the tobacco withdrawal syndrome in humans. These results have implications for defining and assessing tobacco use disorder and for understanding and treating tobacco addiction., ((PsycINFO Database Record (c) 2015 APA, all rights reserved).)

Fluid-induced oscillatory shear stress (OSS) and nicotine are known antagonists in cardiovascular disease. However, from a regenerative medicine standpoint, we hypothesized that these parameters may support the cell differentiation of bone marrow mesenchymal stem cells (BMMSCs) for engineering heart valves. In this study, OSS and nicotine (10-6M) were applied individually to BMMSCs in monolayer culture. In both cases, a significantly higher expression of CD31 was detected compared to corresponding controls (p<0.05). We interpret our findings to indicate that both OSS and nicotine independently support mesenchymal to endothelial transformation; however, the underlying mechanism for this transformation in terms of the cell cytoskeletal structure was entirely different between the two stimulants. In the case of OSS, F-actin filaments exhibited a stretching response and formed a preferential alignment with each other. However, in the nicotine-treated group, a clear increase was observed in the number of actin filaments present, which led to the maximum expression of CD31 in comparison to the OSS and control groups. From our findings, we speculate that while nicotine may stimulate an increase in the differentiation of BMMSCs to endothelial cells, OSS may play a greater role in cellular distribution and the eventual creation of a tissue engineered heart valve (TEHV) endothelium.

Not all smoking addicts can succeed in quitting smoking with willpower only. These people may use nicotine replacement therapy (patches, gums, lozenges, sublingual tablets, inhalers), medicines (bupropion, varenicline and cytisine) and psychological aid. Each drug, besides its therapeutic effect, creates the risk of adverse reactions which number and severity is not always accepted by the patient. The aim of the study was to analyze adverse effects of bupropion, varenicline and cytisine formulations reported by patients. From July 2011 to June 2013 Regional Centre for Monitoring Adverse Drug Reactions (Department of Clinical Pharmacology, Department of Cardiology, Poznan University of Medical Sciences) recorded 32 suspected adverse reactions to the use of drugs for the treatment of nicotine addiction (12 after the preparation of cytisine and varenicline, 8 after preparations of bupropion). High determination caused that none of the patients withdrew from the therapy because of adverse effects.

A primary target for nicotine is the acetylcholine receptor channel (AChR). Some of the ability of nicotine to activate differentially AChR subtypes has been traced to a transmitter-binding site amino acid that is glycine in lower affinity and lysine in higher affinity AChRs. We studied the effects of mutations of this residue (αG153) in neuromuscular AChRs activated by nicotine and eight other agonists including nornicotine and anabasine. All of the mutations increased the unliganded gating equilibrium constant. The affinity of the resting receptor (K(d)) and the net binding energy from the agonist for gating (ΔG(B)) were estimated by cross-concentration fitting of single-channel currents. In all but one of the agonist/mutant combinations there was a moderate decrease in K(d) and essentially no change in ΔG(B). The exceptional case was nicotine plus lysine, which showed a large, >8,000-fold decrease in K(d) but no change in ΔG(B). The extraordinary specificity of this combination leads us to speculate that AChRs with a lysine at position αG153 may be exposed to a nicotine-like compound in vivo.

Drug development for nicotinic acetylcholine receptors (nAChR) is challenged by subtype diversity arising from variations in subunit composition. On-target activity for neuronal heteromeric receptors is typically associated with CNS receptors that contain α4 and other subunits, while off-target activity could be associated with ganglionic-type receptors containing α3β4 binding sites and other subunits, including β4, β2, α5, or α3 as a structural subunit in the pentamer. Additional interest in α3 β4 α5-containing receptors arises from genome-wide association studies linking these genes, and a single nucleotide polymorphism (SNP) in α5 in particular, to lung cancer and heavy smoking. While α3 and β4 readily form receptors in expression system such as the Xenopus oocyte, since α5 is not required for function, simple co-expression approaches may under-represent α5-containing receptors. We used a concatamer of human α3 and β4 subunits to form ligand-binding domains, and show that we can force the insertions of alternative structural subunits into the functional pentamers. These α3β4 variants differ in sensitivity to ACh, nicotine, varenicline, and cytisine. Our data indicated lower efficacy for varenicline and cytisine than expected for β4-containing receptors, based on previous studies of rodent receptors. We confirm that these therapeutically important α4 receptor partial agonists may present different autonomic-based side-effect profiles in humans than will be seen in rodent models, with varenicline being more potent for human than rat receptors and cytisine less potent. Our initial characterizations failed to find functional effects of the α5 SNP. However, our data validate this approach for further investigations., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Much research has implicated the serotonin (5-HT) system in cognitive functioning and psychomotor stimulant abuse, but its role depends on the subtypes of 5-HT receptors involved and the nature of the behavioural task. Here we aimed to extend previous studies by examining the role of 5-HT1A and 5-HT2C receptors in attentional performance. The effects of the selective 5-HT antagonists WAY-100635 and SB-242084 were assessed alone and for interactions with nicotine in the five-choice serial reaction time task in rats. The effects of several doses of WAY-100635 were tested in combination with a fixed dose of nicotine, and then various doses of nicotine were tested in combination with SB-242084. Systemic administration of WAY-100635 and SB-242084 induced opposing effects on speed-related measures in the five-choice serial reaction time task, with antagonism at 5-HT1A receptors increasing omission errors and response latency, and antagonism at 5-HT2C receptors reducing both omissions and latency, and also increasing anticipatory responses; neither drug affected accuracy. Nicotine itself improved all main indices of attention, and there was preliminary evidence that the detrimental effects of WAY-100635 on response latency were weakened by nicotine. Conversely, treatment with SB-242084 enhanced all speed-related indices of performance to above the levels seen under the influence of nicotine alone, thus suggesting that 5-HT2C antagonists might be useful to decrease reaction times if used as an add-on therapy to treat attentional decline.

Background and Purpose: Partial agonists selective for α4β2 nicotinic ACh receptors have been developed for smoking cessation as they induce weak activation of native α4β2* receptors and inhibit effect of nicotine. However, it is unclear whether at brain functions there is an existence of receptor reserve that allows weak receptor activation to induce maximum physiological effects. We assessed the extent of α4β2 partial agonist-induced increase of firing rate in dopaminergic neurons and evaluated the influence of receptor reserve., Experimental Approach: The relative maximal effects and potencies of six nicotinic agonists were assessed on recombinant human α4β2 and α7 receptors expressed in mammalian cell lines by measuring calcium influx. Agonist-induced increase of the spontaneous firing rate of dopaminergic neurons was recorded using microelectrodes in the ventral tegmental area of rat brain slices., Key Results: All α4β2 partial and full agonists increased the firing rate concentration-dependently. Their sensitivity to subtype-selective antagonists showed predominant activation of native α4β2* receptors. However, partial agonists with relative maximal effects as low as 33% on α4β2 receptors maximally increased the firing rate and induced additional depolarization block of firing, demonstrating that partial activation of receptors caused the maximum increase in firing rate in the presence of a receptor reserve., Conclusions and Implications: Partial α4β2 agonists induced relatively enhanced effects on the firing rate of dopaminergic neurons, and the effect was mainly attributed to the existence of native α4β2* receptor reserve. The results have implications in the understanding of physiological effects and therapeutic efficacies of α4β2 partial agonists., (© 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.)

Cigarette smoking is the primary cause of lung cancer, cardiovascular diseases, reproductive disorders, and delayed wound healing all over the world. The goals of smoking cessation are both to reduce health risks and to improve quality of life. The development of novel and more effective medications for smoking cessation is crucial in the treatment of nicotine dependence. Currently, first-line smoking cessation therapies include nicotine replacement products and bupropion. The partial nicotinic receptor agonist, varenicline, has recently been approved by the US Food and Drug Administration (FDA) for smoking cessation. Clonidine and nortriptyline have demonstrated some efficacy, but side effects may limit their use to second-line treatment products. Other therapeutic drugs that are under development include rimonabant, mecamylamine, monoamine oxidase inhibitors, and dopamine D3 receptor antagonists. Nicotine vaccines are among newer products seeking approval from the FDA. Antidrug vaccines are irreversible, provide protection over years and need booster injections far beyond the critical phase of acute withdrawal symptoms. Interacting with the drug in the blood rather than with a receptor in the brain, the vaccines are free of side effects due to central interaction. For drugs like nicotine, which interacts with different types of receptors in many organs, this is a further advantage. Three anti-nicotine vaccines are today in an advanced stage of clinical evaluation. Results show that the efficiency of the vaccines is directly related to the antibody levels, a fact which will help to optimize the vaccine effect. The vaccines are expected to appear on the market between 2011 and 2012.

In a two-year carcinogenicity study with administration of high doses of the partial nicotinic agonist varenicline (recently approved for smoking cessation), mediastinal hibernomas occurred in three male rats. To investigate potential mechanisms for partial and full nicotinic agonists to contribute to development of hibernomas, the effects of nicotine on rat brown adipose tissue (BAT) were studied. Male and female rats were administered nicotine at doses of 0, 0.3, and 1 mg/kg subcutaneously for fourteen days. Intrathoracic (mediastinal periaortic and mediastinal perithymic) BAT and interscapular BAT were examined microscopically, and determinations of uncoupling protein-1 (UCP-1) expression and norepinephrine (NE) content were made. Additionally, NE turnover was measured in mediastinal periaortic and perithymic BAT. Nicotine (1 mg/kg) administration resulted in decreased vacuolation only in mediastinal periaortic and mediastinal perithymic BAT of males and elevated UCP-1 in mediastinal periaortic BAT of males and females. Increased NE content occurred only in mediastinal periaortic BAT of males given 0.3 and 1 mg/kg doses, whereas NE turnover was decreased in both males and females given 1 mg/kg. Together, these data demonstrate that nicotine primarily affects mediastinal BAT in male rats, consistent with the gender and location of the hibernomas observed in the two-year carcinogenicity study.

Nicotine replacement therapies (NRT) were the main pharmacologic option for treatment of nicotine dependence until the early 1990s, when controlled clinical trials confirmed the efficacy of bupropion, the first treatment not based on nicotine. Varenicline, a partial agonist at nicotine receptors, gained US regulatory approval in 2006 for smoking cessation. Although these agents are all effective for nicotine dependence, their efficacy rates vary compared with placebo (overall OR for NRT efficacy, 1.77; for bupropion, 1.94; for varenicline, 3.09). Each of these treatments has a place, sometimes in combinations with other agents, in cancer patients who continue to smoke. Our initial experience with varenicline has been encouraging. Bupropion has specific advantages for cancer patients, including increased energy, low risk for nausea, and decreased weight gain from quitting.

Aims: We conducted a review of published reports of smoking cessation pharmacotherapy trials in order to address the following: (i) the generalizability of findings to smokers with a history of alcohol problems; (ii) the extent to which alcohol use affects smoking cessation overall and the efficacy of pharmacotherapy specifically and (iii) the effect of smoking cessation on alcohol use., Methods: We located published reports of nicotine replacement therapy (NRT), bupropion sustained release (SR) and varenicline clinical trials using an approach based on prior Cochrane reviews. The reports were searched for alcohol-related inclusion/exclusion criteria and for findings related to alcohol., Results: The present review included 212 published reports from 149 trials. Alcohol-related exclusion criteria appeared frequently (41.6% of trials)--45/125 NRT trials (36%), 15/22 bupropion SR trials (68.2%) and 3/3 varenicline trials--and most commonly involved exclusion of participants with either current or recent alcohol problems. Most studies failed to provide any baseline alcohol-related characteristics. Eleven trials reported on the relationship between alcohol history and likelihood of smoking cessation. In the majority of these studies, smokers with a past history of alcohol problems were not at a disadvantage, although contrary findings exist. Only two studies examined the potential influence of smoking cessation on alcohol use., Conclusions: Smokers with alcohol problems, particularly those with current or recent problems, are underrepresented in studies of approved pharmacotherapy for smoking cessation. Future trials should assess alcohol use at baseline and during treatment and examine reciprocal influences between alcohol consumption and smoking cessation.

The hydrogen-bond (HB) interactions of the monocharged active forms of nicotine and acetylcholine (ACh) have been compared theoretically by using density functional theory (DFT) calculations and experimentally on the basis of crystallographic observations and the measurement of equilibrium constants in solution. The 2,4,6-trinitrophenolate (picrate) counterion was used to determine the experimental HB basicity of the cations despite its potential multisite HB acceptor properties. The preferred HB interaction site of the ammonium picrate salts was determined from a survey of crystallographic data found in the Cambridge Structural Database (CSD) and is supported by theoretical calculations. Two distinct classes of ammonium groups were characterised depending on the absence (quaternary ammonium) or presence (tertiary, secondary and primary ammoniums) of an N(+)HO hydrogen bond linking the two ions. The crystal structure of nicotinium picrate was determined and compared with that of ACh. This analysis revealed the peculiar behaviour of the ammonium moiety of nicotinic acetylcholine receptor (nAChR) ligands towards the picrate anion. Dedicated methods have been developed to separate the individual contributions of the anion and cation accepting sites to the overall HB basicity of the ion pairs measured in solution. The HB basicities of the picrate anions associated with the two different ammonium classes were determined in dichloromethane solution by using several model ion pairs with non-basic ammonium cations. The experimental and theoretical studies performed on the nicotine and ACh cations consistently show the significant HB ability of the acceptor site of nAChR agonists in their charged form. Both the greater HB basicity of the pyridinic nitrogen over the carbonyl oxygen and the greater HB acidity of the N(+)H unit relative to N(+)CH could contribute to the higher affinity for nAChRs of nicotine-like ligands relative to ACh-like ligands.

The diversity of neonicotinoid insecticides acting as insect nicotinic acetylcholine (ACh) receptor (nAChR) agonists is illustrated by imidacloprid (IMI) with chloropyridinylmethyl (CPM) and N-nitroimine substituents, dinotefuran (DIN) with tetrahydrofurylmethyl (TFM) and N-nitroimine moieties, and acetamiprid (ACE) with CPM and N-cyanoimine groups. These three neonicotinoids are used here as radioligands to test the hypothesis that they all bind to the same site in the same way in both fruit flies (Drosophila melanogaster) and a leafhopper pest (Homalodisca coagulata): that is, neonicotinoid binding site specificity is conserved in the insect nAChRs. Multiple approaches show that [3H]IMI and [3H]ACE interact with an identical site in both species. However, although [3H]DIN binds with high affinity in both insects, its pharmacological profile in Homalodisca is surprisingly unique, with high sensitivity to some TFM-containing compounds and ACh. The TFM moiety of DIN may bind in a different orientation compared to the CPM group of IMI and ACE.

The medial septal area of conscious rats was stimulated through previously implanted electrodes at a frequency of 7.7 Hz for 20 min each day for 7 days to evoke rhythmic slow activity in CA1 at a similar frequency to spontaneous theta. Two weeks later in the anaesthetized rats the effects of a single subcutaneous injection of nicotine (0.4 mg x kg(-1)) on fEPSPs, evoked in the dentate gyrus by separate stimulation of the MPP and LPP, were studied and compared with those obtained in controls. Nicotine increased the firing of locus coeruleus neurones and the slope of the fEPSPs evoked by LPP stimulation, but not by MPP stimulation. Prior theta driving considerably increased the effect of nicotine on the responses evoked by stimulation of the MPP and abolished the nicotine-induced potentiation of the responses evoked by stimulation of the LPP. The results are attributed to theta driving increasing the amount of noradrenaline released by nicotine and to noradrenaline producing a beta-adrenoceptor long-lasting potentiation at the medial perforant path synapse and a long-lasting depression at the lateral perforant path synapse.

Objective: The leaves of sage (Salvia officinalis L., Lamiaceae) are reported to have a wide range of biological activities, such as anti-bacterial, fungistatic, virustatic, astringent, eupeptic and anti-hydrotic effects. To determine the mnemogenic effect of sage leaves, we investigated the effects of ethanolic extract of sage leaves and its interaction with cholinergic system on memory retention of passive avoidance learning in rats., Methods: Post-training intracerebroventricular (i.c.v.) injections were carried out in all the experiments except ethanolic extract (i.p. intraperitoneally)., Results: Administration of ethanolic extract (50 mg/kg), pilocarpine (0.5 and 1 mg/rat), the muscarinic cholinoceptor agonist, and nicotine (0.1 and 1 microg/rat) increased, while mecamylamine (1, 5 microg/rat), the muscarinic cholinoceptor antagonist, and mecamylamine (0.01 and 0.1 microg/rat), the nicotine cholinoceptor antagonist decreased memory retention in rats. Activation of muscarinic cholinoceptors by pilocarpine potentiated the response of ethanolic extract. Also, pharmacological blockade of scopolamine attenuated potentiating effect of ethanolic extract. Activation of nicotinic cholinoceptor by nicotine potentiated the response of ethanolic extract. Blockade of nicotinic cholinoceptor by mecamylamine attenuated the response of ethanolic extract., Conclusion: It is concluded that the ethanolic extract of salvia officinalis potentiated memory retention and also it has an interaction with muscarinic and nicotinic cholinergic systems that is involved in the memory retention process.

The synthesis of racemic cytisine has been completed using (i)N-selective alkylation of 6-bromopyridone with bromide and (ii) Pd(0) mediated intramolecular alpha-arylation of lactam as key steps to achieve rapid assembly of the tricyclic core skeleton of the lupin alkaloids.

Inflammation of the buccal mucosa, gingiva and periodontal tissues is a significant problem in users of nicotine-containing tobacco products; however, the potential role of nicotine in the development of this inflammation is unclear. In many tissues, nicotine, acting through nicotinic acetylcholine receptors (nAChRs), has been shown to increase the release of the pro-inflammatory mediator calcitonin gene-related peptide (CGRP) thereby potentially contributing to neurogenic inflammation. The purpose of the present studies was to determine the effects of nicotine and other nAChR agonists on capsaicin-evoked immunoreactive CGRP (iCGRP) release from rat buccal mucosa and to identify a potential cellular basis for these effects. Using a previously validated model of in vitro superfusion, we show that the nAChR agonists nicotine (EC50 557 micro m), epibatidine (EC50 317 pm) and cytisine (EC50 4.83 nm) potentiated capsaicin-evoked iCGRP release in a concentration-dependent manner by 123, 70 and 76%, respectively. The expression and distribution patterns of the mRNA transcripts encoding the alpha3, alpha4 and alpha6 nAChR subunits and their colocalization with CGRP and the capsaicin receptor VR1 were examined in rat trigeminal ganglion using combined in situ hybridization and immunohistofluorescence. Of all trigeminal neurons counted, mRNA encoding the alpha3, alpha4 and alpha6 subunits was found, respectively, in 14.45, 9.2 and 19.21% of neurons. The cell body diameter of most neurons containing any nAChR subunit was in the 30-40 micro m range with slightly fewer in the 20-30 micro m range. Co-localization of these alpha subunit transcripts with either CGRP or VR1 immunoreactivity ranged from approximately 5 to 7% for alpha4 and over 8% for alpha3 to 18% for alpha6. These data support the hypothesis that nicotinic agents, acting at nAChRs contained on primary sensory neurons, are capable of directly modulating the stimulated release of iCGRP. In the case of users of nicotine-containing tobacco products, this modulation could contribute to inflammatory processes within the oral cavity.

The electrophysiological actions of various neonicotinoids, including substituted benzyl derivatives, against recombinant Drosophila SAD/chicken beta2 hybrid nicotinic acetylcholine receptor (nAChR) were measured to analyze the relationships between the in vivo (insecticidal) and in vitro (binding and agonist) activities. Most of the neonicotinoids tested were capable of inducing inward currents by activating the hybrid nAChRs expressed in Xenopus laevis oocytes, whereas some compounds had no agonist activity and only blocked the acetylcholine-induced currents. Variations in the agonist activity were well correlated with those in the binding potency evaluated using [3H]imidacloprid as well as insecticidal activities.

We determined the localization of [(3)H]nicotine, [(3)H]cytisine, [(3)H]epibatidine, and [(125)I]alpha-bungarotoxin binding sites in the brain of rhesus monkey by means of receptor autoradiography. The labelings by [(3)H]nicotine, [(3)H]cytisine, and [(3)H]epibatidine were highly concordant, except for epibatidine. Layer IV of some cortical areas, most thalamic nuclei, and presubiculum displayed high levels of labeling for the three ligands. Moderate levels of binding were detected in the subiculum, the septum, and the mesencephalon. Low levels were present in layers I-II and VI of the cortex, the cornu Ammonis, the dentate gyrus, and the amygdala. In addition, the level of epibatidine labeling was very high in the epithalamic nuclei and the interpeduncular nucleus, whereas labeling by nicotine and cytisine was very weak in the same regions. The distribution of [(125)I]alpha-bungarotoxin binding differed from the binding of the three agonists. The labeling was dense in layer I of most cortical areas, dentate gyrus, stratum lacunosum-moleculare of CA1 field, several thalamic nuclei, and medial habenula. A moderate labeling was found in layers V and VI of the prefrontal and frontal cortices, layer IV of primary visual cortex, amygdala, septum, hypothalamus, and some mesencenphalic nuclei. A weak signal was also detected in subiculum, claustrum, stratum oriens, and stratum lucidum of cornu Ammonis and also in some mesencephalic nuclei. The distribution of nicotine, cytisine, and epibatidine bindings corresponds broadly to the patterns observed in rodents, with the marked exception of the epithalamus. However, in monkey, those distributions match the distribution of alpha2 messenger RNA, rather than that of alpha4 transcripts as it exists in rodent brains. The distribution of the binding sites for alpha-bungarotoxin is larger in the brain of rhesus monkeys than in rodent brain, suggesting a more important role of alpha7 receptors in primates., (Copyright 2003 Wiley-Liss, Inc.)

Activation of neuronal nicotinic acetylcholine receptors (nAChRs) has been shown to maintain cognitive function following aging or the development of dementia. Nicotine and nicotinic agonists have been shown to improve cognitive function in aged or impaired subjects. Smoking has also been shown in some epidemiological studies to be protective against the development of neurodegenerative diseases. This is supported by animal studies that have shown nicotine to be neuroprotective both in vivo and in vitro. Treatment with nicotinic agonists may therefore be useful in both slowing the progression of neurodegenerative illnesses, and improving function in patients with the disease. While increased nicotinic function has been shown to be beneficial, loss of cholinergic markers is often seen in patients with dementia, suggesting that decreased cholinergic function could contribute to both the cognitive deficits, and perhaps the neuronal degeneration, associated with dementia. In this article we will review the literature on each of these areas. We will also present hypotheses that might address the mechanisms underlying the ability of nAChR function to protect against neurodegeneration or improve cognition, two potentially distinct actions of nicotine., (Copyright 2002 Wiley Periodicals, Inc.)

Background: Alcoholism is associated with a higher incidence of smoking. The mesolimbic dopaminergic pathway is believed to play an important role in the reinforcing effects of both ethanol and nicotine. This study was undertaken to determine whether simultaneous administration of systemic ethanol and microinjection of nicotine into the ventral tegmental area (VTA) would result in exaggerated release of dopamine (DA) in the shell region of nucleus accumbens., Methods: Microdialysis was applied in awake, freely moving adult male Wistar rats, and DA concentration in the dialysate was measured by HPLC-electrochemical detectors., Results: Systemic administration of ethanol or microinjection of nicotine into VTA resulted in a dose-dependent increase in DA release (extracellular DA concentration). Simultaneous administration of lower doses of nicotine and ethanol resulted in an additive effect on the released DA. This additive effect was not observed with higher doses of nicotine and ethanol. Administration of the nicotinic antagonist mecamylamine into VTA completely blocked ethanol-induced DA release., Conclusions: These data support the hypothesis that the reinforcing effects of ethanol are at least partially mediated through the nicotinic receptors in the VTA. Furthermore, administration of selective nicotinic antagonists may be of therapeutic potential in reducing the rewarding effects of ethanol. The data also suggest that the combined effects of ethanol and nicotine on the "reward pathway" may be a contributing factor to the high incidence of smoking in alcoholics.

1. The aim of this study was to compare the effects of chronic treatment (for 4 or 7 days) with nicotinic drugs and 20 mM KCl on numbers of surface alpha7 nicotinic AChR, identified by [(125)I]-alpha bungarotoxin (alpha-Bgt) binding, in primary hippocampal cultures and SH-SY5Y cells. Numbers of alpha3* nicotinic AChR were also examined in SH-SY5Y cells, using [(3)H]-epibatidine, which is predicted to label the total cellular population of predominantly alpha3beta2* nicotinic AChR under the conditions used. 2. All the nicotinic agonists examined, the antagonists d-tubocurarine and methyllycaconitine, and KCl, upregulated [(125)I]-alpha Bgt binding sites by 20 - 60% in hippocampal neurones and, where examined, SH-SY5Y cells. 3. Upregulation of [(125)I]-alpha-Bgt binding sites by KCl was prevented by co-incubation with the L-type Ca2+ channel blocker verapamil or the Ca2+-calmodulin dependent kinase II (CaM-kinase II) inhibitor KN-62. Upregulation of [(125)I]-alpha-Bgt binding sites by nicotine or 3,[(4-dimethylamino) cinnamylidene] anabaseine maleate (DMAC) was insensitive to these agents. 4. [(3)H]-Epibatidine binding sites in SH-SY5Y cells were not affected by KCl but were upregulated in a verapamil-insensitive manner by nicotine and DMAC. KN-62 itself provoked a 2 fold increase in [(3)H]-epibatidine binding. The inactive analogue KN-04 had no effect, suggesting that CaM-kinase II plays a role in regulating numbers of alpha3* nicotinic AChR. 5. These data indicate that numbers of alpha3* and alpha7 nicotinic AChR are modulated differently. Nicotinic agonists and KCl upregulate alpha7 nicotinic AChR through distinct cellular mechanisms, the latter involving L-type Ca2+ channels and CaM-kinase II. In contrast, alpha3* nicotinic AChR are not upregulated by KCl. This difference may reflect the distinct physiological roles proposed for alpha7 nicotinic AChR.

Background: Smoking cessation clinical practice guidelines are based on randomised clinical trials reporting outcomes in persons who participate in these studies. However, many practitioners are sceptical about the effectiveness of these recommendations when applied to the general population in everyday routine consultation., Aim: To evaluate the results of a comprehensive smoking cessation programme in routine primary care practice., Method: All smokers consulting in 10 general practices during one year participated in a non-randomised controlled trial. The percentages of subjects in the intervention (n = 1203, seven practices) and control (n = 565, three practices) groups who reported sustained abstinence between six and 12 months follow-up and were validated biochemically were compared. The effect of the programme was adjusted to baseline differences in both groups by multiple logistic regression analyses., Results: The programme resulted in an increase of five percentage points (95% CI = 3.1%-6.8%) in the validated and sustained one-year abstinence probability, with 7.1% for all of the intervention practices (adjusted OR = 3.7, 95% CI = 2.4-5.7)., Conclusion: Programmes that combine advice to stop smoking to all smokers attending general practices with the offering of support, follow-up, and nicotine patches to those willing to stop are feasible and effective in routine practice, as primary care clinicians need only identify 20 smokers to get one additional success attributable to the programme.

Neuronal nicotinic acetylcholine receptors (nAChRs) represent a large family of ligand-gated cation channels with diverse structures and properties. In contrast to the muscular nAChRs, the physiological functions of neuronal nAChRs are not well defined to date. Behavioral studies indicate that brain nAChRs participate in complex functions such as attention, memory, and cognition, whereas clinical data suggest their involvement in the pathogenesis of certain neuropsychiatric disorders (Alzheimer's and Parkinson's diseases, Tourette's syndrome, schizophrenia, depression, etc.). For the majority of these disorders, the use of nAChRs' agonists may represent either a prophylactic (especially for Alzheimer's and Parkinson's diseases) or a symptomatic treatment. The possible mechanisms underlying these beneficial effects as well as the characteristics and potential therapeutic use of new, subtype-selective nAChRs agonists are presented.

A number of epidemiological studies suggest that estrogen therapy is linked to a reduced risk of developing Alzheimer's disease (AD). The present study was conducted to evaluate the effect of 17beta-estradiol on beta-amyloid (Abeta)-induced toxicity and was performed in rat pheochromocytoma PC 12 cells by measuring the mitochondrial activity. 17Beta-estradiol (10(-5), 10(-6) and 10(-8) M) attenuated Abeta(25-35)-induced toxicity in PC 12 cells. The neuroprotective effect of 17beta-estradiol (10(-5) M) was prevented in the presence of the nicotinic antagonists methyllycaconitine (MLA) and mecamylamine, suggesting an interaction probably via the alpha7 nicotinic receptor subtype. Chronic treatment with 17beta-estradiol (10(-10)-10(-5) M) alone did not change the number of [3H]epibatidine binding sites in human neuroblastoma SH-SY5Y cells and rat PC 12 cells, but significantly prevented the enhanced [3H]epibatidine binding in nicotine-treated PC 12 cells. This study demonstrates that 17beta-estradiol exerts neuroprotective effects which might involve interaction with the alpha7 nicotinic receptor subtype.

The effects of the nicotinic agonists acetylcholine, (+)-anatox in-a, carbachol, cytisine, dimethylphenylpiperazinum, (+)-epibatidine, (-)-epibatidine, methylcarbachol, D-nicotine, L-nicotine, and tetramethylammonium on 86Rb+ efflux from mouse thalamic synaptosomes were investigated. All 11 agonists evoked a concentration-dependent stimulation of 86Rb+ efflux as well as a time- and concentration-dependent reduction of response (desensitization). The agonists varied widely in potency, efficacy and rate of desensitization. (+)-Epibatidine was the most potent agonist (EC50 = 10 nM), whereas tetramethylammonium was the least potent (EC50 = 65 microM). The agonists containing a quaternary ammonium group were generally more efficacious than the other agonists, except for both of the enantiomers of epibatidine, which stimulated 86Rb+ efflux at least as well as acetylcholine. Cytisine was the least efficacious compound tested with a maximal response approximately 10% that of (-)-epibatidine. Exposure of the thalamic synaptosomes to agonist concentrations that generally stimulated little or no efflux reduced in a concentration-dependent manner a subsequent response to 10 microM nicotine. The IC50 values for this functional blockade (desensitization) were highly correlated with the Ki values for the inhibition of [3H]nicotine binding. Furthermore, exposure of the thalamic synaptosomes to 300 nM L-nicotine reduced the responses evoked by a subsequent exposure to a stimulating concentration of all 11 agonists. The observation of desensitization by both stimulating and substimulating concentrations of each agonist is consistent with the predictions of the two-state model of Katz and Thesleff.

We have examined the effects of the muscarinic agonists, carbachol (CCh) and oxotremorine (Oxo), on the intracellular free Ca2+ concentration ([Ca2+]i) in acutely dissociated sympathetic neurons from adult rats using fura 2-based microfluorometry. The drugs increased [Ca2+]i by 86 +/- 7 and 38 +/- 10 nM for CCh and Oxo, respectively (both 10 microM). Basal [Ca2+]i was 52 +/- 3 nM. Depletion of the caffeine-sensitive Ca2+ store or blockade of the Ca(2+)-adenosinetriphosphatase with thapsigargin did not alter the effect of either agonist on the rise in [Ca2+]i. On the other hand, the omission of Ca2+ from the perfusion solution or the use of TA-3090, a Ca2+ channel antagonist, blocked the effects of CCh and Oxo. In whole cell current-clamp recordings, the muscarinic agonists elicited a depolarization and action potential firing, which probably explained the rise in [Ca2+]i observed with microfluorimetric recording. In addition to their direct effects on the [Ca2+]i, muscarinic agonists also reduced the rise in [Ca2+]i induced by a nicotinic agonist. This inhibitory effect, observed in 68% of cells that responded to the nicotinic agonist, was blocked by atropine and pertussis toxin, whereas the muscarinic agonist-induced increase in [Ca2+]i was blocked by atropine but was pertussis toxin insensitive. These results suggest that at least two muscarinic receptors are present on sympathetic neurons and that they mediate opposite effect on the fluctuation of [Ca2+]i.

Nicotinic cholinergic agonists stimulate ACTH secretion by a central mechanism involving brainstem catecholamines. In vivo microdialysis studies were conducted to measure the release of norepinephrine (NE) in the hypothalamic paraventricular nucleus (PVN) in response to the administration of nicotine (Nic) or another nicotinic cholinergic (NAch) agonist, cytisine (Cyt), directly into the IVth ventricle. Alert, freely mobile rats, equipped 24 h previously with a chronic guide cannula in the IVth ventricle and microdialysis probe in the PVN, were injected with artificial cerebrospinal fluid (CSF, 500 nl/60 s), Nic (1-5 micrograms), or Cyt (1-25 micrograms) after three 20-min baseline samples had been taken. Analysis of the dialysates by HPLC with electrochemical detection demonstrated the dose-dependent secretion of PVN NE to Nic or Cyt with ED50s of approximately 1 or 6 micrograms, respectively; these were completely blocked by prior IVth ventricular injection of the NAch antagonist, mecamylamine (4 micrograms). In contrast, alpha-bungarotoxin, which antagonizes the action of NAch agonists by acting through the alpha 7 bungarotoxin-type NAchR, failed to reduce the NE response to Nic. Partial, but significant desensitization of NE secretion in response to a second injection of Nic (2.5 or 5 micrograms) 100 min after the first was seen, whereas NE responses to the second injection of Cyt (5 or 25 micrograms) were completely desensitized. However, cross-desensitization of each agonist to the other did not occur. This may reflect heterogeneity of the NAch receptor subtypes involved. The results of this study establish a correlation between the action of nicotine on brainstem norepinephrinergic regions and the resultant release of NE in the PVN, which would lead to the release of ACTH secretagogues.

The effects of nicotine and related compounds on locomotor activity were compared in experimentally naive rats and in animals chronically exposed to nicotine and the photocell test chambers. In experimentally naive rats, all nicotinic compounds decreased locomotion in a dose-related manner and the rank order of potency was (-)-nicotine > (+)-nornicotine > (+)-nicotine > cytisine > lobeline > anabasine. Mecamylamine attenuated the locomotor depressant effects of most of the agonists, except lobeline. In rats previously exposed to nicotine and the test apparatus for several weeks, (-)-nicotine increased locomotor activity in a dose-related manner, with a maximal increase to 400% of baseline at a dose of 0.4 mg/kg. One or more doses of (+)-nicotine, (+)-nornicotine and anabasine also increased locomotor activity in these animals, although the maximal effects seen were in all cases less than the maximal effect of (-)-nicotine. Cytisine and lobeline failed to increase locomotor activity at any dose tested. These conclusions were not altered by consideration of the time-courses for the effects of the different drugs. Thus, the results confirm that the locomotor stimulant and depressant effects of nicotine can be dissociated from each other, a finding that may be explained by differences in their actions at nicotinic receptors.

It is recognized that tumor necrosis factor-alpha (TNF-alpha), a pleiotropic cytokine, influences hormone secretion and transmitter release from central neurons. To examine the role of TNF-alpha as a modulator of autonomic function of the PNS, we measured [3H]norepinephrine ([3H]NE) secretion evoked by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), a nicotinic agonist, in cultures from neonatal rat superior cervical ganglia (SCG). We found that (1) DMPP-evoked [3H]NE secretion was enhanced in SCG mixed cultures treated for 48 h with recombinant human TNF-alpha (rhTNF-alpha) plus rat interferon-gamma (IFN-gamma) but not in cultures treated with either cytokine alone; (2) an increase in [3H]NE secretion was also observed in mixed cultures treated with recombinant murine TNF-alpha (rmTNF-alpha) alone; and (3) the presence of nonneuronal cells or soluble factors released by them was required for the effect of these cytokines on secretion. Electrophysiologic experiments revealed an increase in nicotinic receptor current density in neurons from mixed cultures treated with rhTNF-alpha plus IFN-gamma or with rmTNF-alpha when compared with control cultures. We conclude that prolonged exposure to rhTNF-alpha plus IFN-gamma or rmTNF-alpha regulates nicotinic responses in SCG cultures via a soluble factor or factors secreted by nonneuronal cells.