101
|
Direct effect of nicotine on mesolimbic dopamine release in rat nucleus accumbens shell. Neurosci Lett 2011; 493:55-8. [DOI: 10.1016/j.neulet.2011.02.035] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 02/15/2011] [Accepted: 02/15/2011] [Indexed: 11/19/2022]
|
102
|
Mascia P, Pistis M, Justinova Z, Panlilio LV, Luchicchi A, Lecca S, Scherma M, Fratta W, Fadda P, Barnes C, Redhi GH, Yasar S, Le Foll B, Tanda G, Piomelli D, Goldberg SR. Blockade of nicotine reward and reinstatement by activation of alpha-type peroxisome proliferator-activated receptors. Biol Psychiatry 2011; 69:633-41. [PMID: 20801430 PMCID: PMC2994947 DOI: 10.1016/j.biopsych.2010.07.009] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Revised: 07/08/2010] [Accepted: 07/09/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Recent findings indicate that inhibitors of fatty acid amide hydrolase (FAAH) counteract the rewarding effects of nicotine in rats. Inhibition of FAAH increases levels of several endogenous substances in the brain, including the endocannabinoid anandamide and the noncannabinoid fatty acid ethanolamides oleoylethanolamide (OEA) and palmitoylethanolamide, which are ligands for alpha-type peroxisome proliferator-activated nuclear receptors (PPAR-α). Here, we evaluated whether directly acting PPAR-α agonists can modulate reward-related effects of nicotine. METHODS We combined behavioral, neurochemical, and electrophysiological approaches to evaluate effects of the PPAR-α agonists [[4-Chloro-6-[(2,3-dimethylphenyl)amino]-2-pyrimidinyl]thio]acetic acid (WY14643) and methyl oleoylethanolamide (methOEA; a long-lasting form of OEA) on 1) nicotine self-administration in rats and squirrel monkeys; 2) reinstatement of nicotine-seeking behavior in rats and monkeys; 3) nicotine discrimination in rats; 4) nicotine-induced electrophysiological activity of ventral tegmental area dopamine neurons in anesthetized rats; and 5) nicotine-induced elevation of dopamine levels in the nucleus accumbens shell of freely moving rats. RESULTS The PPAR-α agonists dose-dependently decreased nicotine self-administration and nicotine-induced reinstatement in rats and monkeys but did not alter food- or cocaine-reinforced operant behavior or the interoceptive effects of nicotine. The PPAR-α agonists also dose-dependently decreased nicotine-induced excitation of dopamine neurons in the ventral tegmental area and nicotine-induced elevations of dopamine levels in the nucleus accumbens shell of rats. The ability of WY14643 and methOEA to counteract the behavioral, electrophysiological, and neurochemical effects of nicotine was reversed by the PPAR-α antagonist 1-[(4-Chlorophenyl)methyl]-3-[(1,1-dimethylethyl)thio]-a,a-dimethyl-5-(1-methylethyl)-1H-Indole-2-propanoic acid (MK886). CONCLUSIONS These findings indicate that PPAR-α might provide a valuable new target for antismoking medications.
Collapse
Affiliation(s)
- Paola Mascia
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Medications Discovery Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland 21224, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
103
|
Midde NM, Gomez AM, Harrod SB, Zhu J. Genetically expressed HIV-1 viral proteins attenuate nicotine-induced behavioral sensitization and alter mesocorticolimbic ERK and CREB signaling in rats. Pharmacol Biochem Behav 2011; 98:587-97. [PMID: 21420997 DOI: 10.1016/j.pbb.2011.03.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 03/07/2011] [Accepted: 03/12/2011] [Indexed: 12/29/2022]
Abstract
The prevalence of tobacco smoking in HIV-1 positive individuals is 3-fold greater than that in the HIV-1 negative population; however, whether HIV-1 viral proteins and nicotine together produce molecular changes in mesolimbic structures that mediate psychomotor behavior has not been studied. This study determined whether HIV-1 viral proteins changed nicotine-induced behavioral sensitization in HIV-1 transgenic (HIV-1Tg) rats. Further, we examined cAMP response element binding protein (CREB) and extracellular regulated kinase (ERK1/2) signaling in the prefrontal cortex (PFC), nucleus accumbens (NAc) and ventral tegmental area (VTA). HIV-1Tg rats exhibited a transient decrease of activity during habituation, but showed attenuated nicotine (0.35mg/kg, s.c.)-induced behavioral sensitization compared to Fisher 344 (F344) rats. The basal levels of phosphorylated CREB and ERK2 were lower in the PFC of HIV-1Tg rats, but not in the NAc and VTA, relative to the controls. In the nicotine-treated groups, the levels of phosphorylated CREB and ERK2 in the PFC were increased in HIV-1Tg rats, but decreased in F344 animals. Moreover, repeated nicotine administration reduced phosphorylated ERK2 in the VTA of HIV-1Tg rats and in the NAc of F344 rats, but had no effect on phosphorylated CREB, indicating a region-specific change of intracellular signaling. These results demonstrate that HIV-1 viral proteins produce differences in basal and nicotine-induced alterations in CREB and ERK signaling that may contribute to the alteration in psychomotor sensitization. Thus, HIV-1 positive smokers are possibly more vulnerable to alterations in CREB and ERK signaling and this has implications for motivated behavior, including tobacco smoking, in HIV-1 positive individuals who self-administer nicotine.
Collapse
Affiliation(s)
- Narasimha M Midde
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA
| | | | | | | |
Collapse
|
104
|
Rahman S. Brain nicotinic receptors as emerging targets for drug addiction: neurobiology to translational research. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:349-65. [PMID: 21199776 DOI: 10.1016/b978-0-12-385506-0.00008-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Drug addiction, a chronic relapsing disorder, is a serious public health problem around the world. A growing body of preclinical and clinical evidence suggests that mammalian brain nicotinic acetylcholine receptors (nAChRs), the heterogeneous family of ion channels, play a pivotal role in drug addiction, including nicotine and alcohol dependence. As a result, there is an increasing interest in developing nAChR-based therapies for the treatment of addictive disorders. The current review summarizes the important preclinical and clinical data, demonstrating the ability of nAChR ligands to modulate nicotine and alcohol-induced biobehavioral and neurochemical changes in laboratory animals and humans. Recent studies suggest that partial agonists and antagonists at nAChRs have therapeutic potential for the management of nicotine and alcohol dependence. The complexity of nAChRs and their regulation for the development of nAChR-based drug candidates as novel pharmacotherapy for other addictive disorders will also be discussed. Taken together, this review will provide new insights into nAChR-based compounds and offer innovative translational strategies for combating drug addictive disorders.
Collapse
Affiliation(s)
- Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, South Dakota, USA
| |
Collapse
|
105
|
Varenicline attenuates cue-induced relapse to alcohol, but not nicotine seeking, while reducing inhibitory response control. Psychopharmacology (Berl) 2011; 216:267-77. [PMID: 21331520 PMCID: PMC3121941 DOI: 10.1007/s00213-011-2213-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 01/27/2011] [Indexed: 11/17/2022]
Abstract
RATIONALE Treatment of the most widely abused drugs, nicotine and alcohol, is hampered by high rates of relapse. Varenicline tartrate, an α4β2 nicotinic receptor partial agonist, is currently prescribed as a smoking cessation aid. However, there is emerging evidence that it may also modulate alcohol seeking and cognitive functioning in rats. OBJECTIVES As preclinical data on alcohol taking and relapse are limited, we used a self-administration-reinstatement model to evaluate the effects of varenicline on operant responding for alcohol (12%, v/v), intravenous nicotine (40 μg/kg/inf.), sucrose (10%, w/v) and on cue-induced relapse to alcohol and nicotine seeking in rats. At the cognitive level, we assed varenicline's effects on 5-choice serial reaction time task (5-CSRTT) performance with a focus on correct responses (attention) and premature responding (impulsivity), modalities that have previously been associated with addictive behaviour. RESULTS Varenicline, at doses of 1.5 and 2.5 mg/kg, reduced alcohol and nicotine self-administration and enhanced operant responding for sucrose. At these doses, varenicline reduced cue-induced relapse to alcohol, but not nicotine seeking. In contrast, at 0.5 mg/kg, varenicline facilitated cue-induced nicotine seeking. Similar to nicotine, varenicline increased premature responding at low doses, but had no effect on any of the other behavioural parameters in the 5-CSRTT. CONCLUSIONS Our data indicate that varenicline specifically reduced responding for nicotine and alcohol, but not for natural reinforcers such as sucrose. Interestingly, varenicline strongly attenuated cue-induced relapse to alcohol seeking, but not nicotine seeking. Varenicline may therefore be a promising aid in the treatment of alcohol addiction.
Collapse
|
106
|
Berrendero F, Robledo P, Trigo JM, Martín-García E, Maldonado R. Neurobiological mechanisms involved in nicotine dependence and reward: participation of the endogenous opioid system. Neurosci Biobehav Rev 2010; 35:220-31. [PMID: 20170672 PMCID: PMC2908214 DOI: 10.1016/j.neubiorev.2010.02.006] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 01/07/2023]
Abstract
Nicotine is the primary component of tobacco that maintains the smoking habit and develops addiction. The adaptive changes of nicotinic acetylcholine receptors produced by repeated exposure to nicotine play a crucial role in the establishment of dependence. However, other neurochemical systems also participate in the addictive effects of nicotine including glutamate, cannabinoids, GABA and opioids. This review will cover the involvement of these neurotransmitters in nicotine addictive properties, with a special emphasis on the endogenous opioid system. Thus, endogenous enkephalins and beta-endorphins acting on mu-opioid receptors are involved in nicotine-rewarding effects, whereas opioid peptides derived from prodynorphin participate in nicotine aversive responses. An up-regulation of mu-opioid receptors has been reported after chronic nicotine treatment that could counteract the development of nicotine tolerance, whereas the down-regulation induced on kappa-opioid receptors seems to facilitate nicotine tolerance. Endogenous enkephalins acting on mu-opioid receptors also play a role in the development of physical dependence to nicotine. In agreement with these actions of the endogenous opioid system, the opioid antagonist naltrexone has shown to be effective for smoking cessation in certain sub-populations of smokers.
Collapse
Affiliation(s)
- Fernando Berrendero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Patricia Robledo
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
- Municipal Institute of Medical Research (IMIM), Barcelona, Spain
| | - José Manuel Trigo
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Elena Martín-García
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| |
Collapse
|
107
|
Kim MN, Jutkiewicz EM, Zhang M, Gnegy ME. The sensitizing effect of acute nicotine on amphetamine-stimulated behavior and dopamine efflux requires activation of β2 subunit-containing nicotinic acetylcholine receptors and glutamate N-methyl-D-aspartate receptors. Neuropharmacology 2010; 60:1126-34. [PMID: 20971124 DOI: 10.1016/j.neuropharm.2010.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/22/2010] [Accepted: 10/06/2010] [Indexed: 12/28/2022]
Abstract
Nicotine has been demonstrated to enhance the subsequent use of illicit drugs in animals and humans. We previously demonstrated in female, Holtzman rats that one low dose of nicotine will potentiate locomotor activity and dopamine (DA) efflux in response to a subsequent low dose of d-amphetamine (AMPH) given 1-4 h later. In the present study, we show this also occurs in male rats and characterize the receptors required for the rapid sensitizing effect of nicotine on AMPH-stimulated locomotor behavior and AMPH-induced DA efflux. Pretreatment of male, Holtzman rats with a low dose (0.1 mg/kg, i.p.) of nicotine 2-4 h before a challenge with AMPH (0.32 mg/kg, i.p.) enhanced locomotor behavior as compared to saline pretreatment. Dihydro-β-erythroidine (DHβE), a relatively selective antagonist at β2 subunit-containing (β2∗) nicotinic acetylcholine receptors (nAChR), but not methyllycaconitine (MLA), a relatively selective antagonist at α7 nAChRs, blocked the sensitizing effect of nicotine on AMPH-stimulated locomotor activity. Pretreatment with varenicline, a partial agonist selective for β2∗ nAChRs, blocked the sensitizing effect of nicotine on AMPH-stimulated locomotor behavior. Nicotine pretreatment sensitized AMPH-induced DA overflow in slices from ventral (nucleus accumbens, NAc), but not dorsal striatum as compared to saline-pretreated rats. Nicotine sensitization of the DA overflow was blocked by DHβE. Pretreatment with the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist (+)-MK-801 (0.1 mg/kg, s.c.) 30 min before nicotine blocked sensitization of both locomotion and DA overflow in response to AMPH challenge. These results demonstrate that activation of the β2∗ nAChRs and NMDA receptors are required for the rapid sensitizing effect of nicotine on AMPH actions. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'.
Collapse
Affiliation(s)
- Myung N Kim
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Science Research Building III, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5632, USA
| | | | | | | |
Collapse
|
108
|
Brody AL, London ED, Olmstead RE, Allen-Martinez Z, Shulenberger S, Costello MR, Abrams AL, Scheibal D, Farahi J, Shoptaw S, Mandelkern MA. Smoking-induced change in intrasynaptic dopamine concentration: effect of treatment for Tobacco Dependence. Psychiatry Res 2010; 183:218-24. [PMID: 20682457 PMCID: PMC2947623 DOI: 10.1016/j.pscychresns.2009.06.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 06/12/2009] [Accepted: 06/17/2009] [Indexed: 11/29/2022]
Abstract
The aim of this study was to determine whether standard treatments for Tobacco Dependence affect smoking-induced changes in intrasynaptic dopamine (DA) concentration. Forty-three otherwise healthy adult cigarette smokers (10 to 40 cigarettes per day) were treated with either practical group counseling (PGC) psychotherapy (n=14), bupropion HCl (n=14), or matching pill placebo (n=15) (random assignment) for 8 weeks. Before and after treatment, each subject underwent a bolus-plus-continuous-infusion (11)C-raclopride positron emission tomography (PET) scanning session, during which he or she smoked a regular cigarette. The PET scanning outcome measure of interest was percent change in smoking-induced (11)C-raclopride binding potential (BP(ND)) in the ventral caudate/nucleus accumbens (VCD/NAc), as an indirect measure of DA release. Although the entire study sample had a smaller mean smoking-induced reduction in VCD/NAc BP(ND) after treatment (compared to before treatment), this change was highly correlated with smaller total cigarette puff volumes (and not other treatment variables). These data indicate that smoking-induced DA release is dose-dependent, and is not significantly affected by reductions in daily smoking levels or treatment type.
Collapse
Affiliation(s)
- Arthur L Brody
- Department of Psychiatry, UCLA, Los Angeles, CA 90095, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
109
|
Improgo MRD, Scofield MD, Tapper AR, Gardner PD. From smoking to lung cancer: the CHRNA5/A3/B4 connection. Oncogene 2010; 29:4874-84. [PMID: 20581870 PMCID: PMC3934347 DOI: 10.1038/onc.2010.256] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 05/17/2010] [Accepted: 05/27/2010] [Indexed: 12/21/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that modulate key physiological processes ranging from neurotransmission to cancer signaling. These receptors are activated by the neurotransmitter, acetylcholine, and the tobacco alkaloid, nicotine. Recently, the gene cluster encoding the alpha3, alpha5 and beta4 nAChR subunits received heightened interest after a succession of linkage analyses and association studies identified multiple single-nucleotide polymorphisms in these genes that are associated with an increased risk for nicotine dependence and lung cancer. It is not clear whether the risk for lung cancer is direct or an effect of nicotine dependence, as evidence for both scenarios exist. In this study, we summarize the body of work implicating nAChRs in the pathogenesis of lung cancer, with special focus on the clustered nAChR subunits and their emerging role in this disease state.
Collapse
Affiliation(s)
- Ma. Reina D. Improgo
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont St., Worcester, Massachusetts USA 01604
| | - Michael D. Scofield
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont St., Worcester, Massachusetts USA 01604
| | - Andrew R. Tapper
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont St., Worcester, Massachusetts USA 01604
| | - Paul D. Gardner
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont St., Worcester, Massachusetts USA 01604
| |
Collapse
|
110
|
Rezvani AH, Slade S, Wells C, Petro A, Lumeng L, Li TK, Xiao Y, Brown ML, Paige MA, McDowell BE, Rose JE, Kellar KJ, Levin ED. Effects of sazetidine-A, a selective alpha4beta2 nicotinic acetylcholine receptor desensitizing agent on alcohol and nicotine self-administration in selectively bred alcohol-preferring (P) rats. Psychopharmacology (Berl) 2010; 211:161-74. [PMID: 20535453 PMCID: PMC3695635 DOI: 10.1007/s00213-010-1878-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 04/28/2010] [Indexed: 11/28/2022]
Abstract
RATIONALE Manipulations of nicotinic cholinergic receptors have been shown to influence both alcohol and nicotine intake. Sazetidine-A [6-(5(((S)-azetidine-2-yl)methoxy)pyridine-3-yl)hex-5-yn-1-ol] is a novel compound that potently and selectively desensitizes alpha4beta2 nicotinic receptors with only modest receptor activation. OBJECTIVES The goal of the present study was to examine the effects of sazetidine-A on alcohol and nicotine self-administration in alcohol-preferring (P) rats. METHODS P rats were given the choice of water or alcohol. Once stable baselines were established, the acute (0, 0.1, 0.3, 1, and 3 mg/kg, s.c.) and chronic (3 mg/kg for 10 days) effects of sazetidine-A on alcohol intake were assessed. Naltrexone (2.5 mg/kg) served as a positive control. The effect of sazetidine-A (3 mg/kg) and naltrexone (4 mg/kg) on saccharin (0.2%) preference was also assessed. In addition, the acute effects of sazetidine-A (3 mg/kg) and naltrexone (4 mg/kg) on alcohol intake after alcohol deprivation were evaluated. In another experiment, the effects of sazetidine-A (0, 1, or 3 mg/kg) on i.v. nicotine self-administration in P and NP rats were assessed. RESULTS Sazetidine-A caused a dose-dependent reduction in alcohol intake. Chronic sazetidine-A also effectively reduced alcohol intake until the seventh day of treatment, when partial tolerance appeared to develop. In the post-deprivation study, sazetidine-A significantly reduced alcohol intake and preference. Sazetidine-A at 3 mg/kg significantly reduced nicotine self-administration in both lines. CONCLUSIONS Sazetidine-A significantly reduced alcohol and nicotine intake in P rats that self-administer higher levels of both drugs. Sazetidine-A may hold promise for the treatment of alcohol and nicotine addiction.
Collapse
Affiliation(s)
- Amir H. Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| | - Susan Slade
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| | - Cori Wells
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| | - Ann Petro
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| | - Lawrence Lumeng
- Department of Internal Medicine, University of Indiana, Indianapolis, IN, USA
| | - Ting-Kai Li
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| | - Yingxian Xiao
- Department of Pharmacology, Georgetown University School of Medicine, Washington, DC, USA
| | - Milton L. Brown
- Department of Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, USA
| | - Mikell A. Paige
- Department of Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, USA
| | - Brian E. McDowell
- Department of Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, USA
| | - Jed E. Rose
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| | - Kenneth J. Kellar
- Department of Pharmacology, Georgetown University School of Medicine, Washington, DC, USA
| | - Edward D. Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC 27710, USA
| |
Collapse
|
111
|
Effects of dopamine antagonists on drug cue-induced reinstatement of nicotine-seeking behavior in rats. Behav Pharmacol 2010; 21:153-60. [PMID: 20168211 DOI: 10.1097/fbp.0b013e328337be95] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Dopaminergic neurotransmission has been implicated in associative learning processes related to drugs of abuse. However, it is not clear whether blockade of activation of dopamine receptors alters conditioned incentive properties of nicotine-associated cues. Using a response-reinstatement procedure, this study examined the effects of antagonists selective for the D1 and the D2 subtypes of dopamine receptors on cue-induced reinstatement of nicotine-seeking behavior. Male Sprague-Dawley rats were trained in 30 daily 1 h sessions to intravenously self-administer nicotine (0.03 mg/kg/infusion) on a fixed ratio 5 schedule and associate a conditioned stimulus (cue) with each nicotine delivery. After extinction of responding by withholding nicotine (saline substitution) and its cue, the reinstatement tests were conducted following subcutaneous administration of a D1 antagonist SCH23390 (0, 5, 10, 30 microg/kg) or a D2 antagonist eticlopride (0, 5, 10, 30 microg/kg) in different groups of animals. Both SCH23390 and eticlopride significantly attenuated the magnitude of cue-elicited reinstatement of nicotine-seeking responding. These results indicate that activation of dopaminergic D1 and D2 receptors may play a role in mediating the conditioned motivational effects of nicotine-associated cues as measured in the response-reinstatement procedure. These findings suggest that manipulation of dopaminergic neurotransmission at D1 and/or D2 receptors may prove to be a potential target for the development of pharmacotherapy for prevention of environmental nicotine cue-triggered smoking relapse.
Collapse
|
112
|
Brennan KA, Lea RA, Fitzmaurice PS, Truman P. Nicotinic receptors and stages of nicotine dependence. J Psychopharmacol 2010; 24:793-808. [PMID: 19251827 DOI: 10.1177/0269881108100256] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Smoking is one of the leading causes of preventable death, where nicotine has been identified as the primary addictive constituent of tobacco. Consequently, there have been extensive investigations into the neuroadaptations that occur as nicotine dependence develops, where numerous neurological systems have been implicated. The focus of this review was on nicotinic acetylcholine receptor neuroadaptations that occur during the development of nicotine dependence. This focus was selected because (1) the nicotinic receptors are the primary binding sites for both nicotine and the most efficacious pharmacological smoking cessation treatments and (2) the receptors are located throughout the brain with considerable neuromodulatory ability. However, there was difficulty associated in outlining the role of nicotinic receptors in the development of nicotine dependence because it comprises a series of stages involving different neurological systems rather than a single state. To address this issue, the review adopts a novel approach and considers the role of nicotinic receptor subtypes at separate stages of the nicotine dependence cycle. This information was then used to examine the nicotinic receptor-related therapeutic mechanisms of three main pharmacological smoking cessation treatments.
Collapse
Affiliation(s)
- K A Brennan
- Environmental Science and Research Ltd, Porirua, Wellington, New Zealand.
| | | | | | | |
Collapse
|
113
|
Lester DB, Rogers TD, Blaha CD. Acetylcholine-dopamine interactions in the pathophysiology and treatment of CNS disorders. CNS Neurosci Ther 2010; 16:137-62. [PMID: 20370804 PMCID: PMC6493877 DOI: 10.1111/j.1755-5949.2010.00142.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Dopaminergic neurons in the substantia nigra pars compacta and ventral tegmental area of the midbrain form the nigrostriatal and mesocorticolimbic dopaminergic pathways that, respectively, project to dorsal and ventral striatum (including prefrontal cortex). These midbrain dopaminergic nuclei and their respective forebrain and cortical target areas are well established as serving a critical role in mediating voluntary motor control, as evidenced in Parkinson's disease, and incentive-motivated behaviors and cognitive functions, as exhibited in drug addiction and schizophrenia, respectively. Although it cannot be disputed that excitatory and inhibitory amino acid-based neurotransmitters, such as glutamate and GABA, play a vital role in modulating activity of midbrain dopaminergic neurons, recent evidence suggests that acetylcholine may be as important in regulating dopaminergic transmission. Midbrain dopaminergic cell tonic and phasic activity is closely dependent upon projections from hindbrain pedunculopontine and the laterodorsal tegmental nuclei, which comprises the only known cholinergic inputs to these neurons. In close coordination with glutamatergic and GABAergic activity, these excitatory cholinergic projections activate nicotinic and muscarinic acetylcholine receptors within the substantia nigra and ventral tegmental area to modulate dopamine transmission in the dorsal/ventral striatum and prefrontal cortex. Additionally, acetylcholine-containing interneurons in the striatum also constitute an important neural substrate to provide further cholinergic modulation of forebrain striatal dopaminergic transmission. In this review, we examine neurological and psychopathological conditions associated with dysfunctions in the interaction of acetylcholine and dopamine and conventional and new pharmacological approaches to treat these disorders.
Collapse
Affiliation(s)
- Deranda B Lester
- Department of Psychology, The University of Memphis, Memphis, TN, USA
| | - Tiffany D. Rogers
- Department of Psychology, The University of Memphis, Memphis, TN, USA
| | - Charles D. Blaha
- Department of Psychology, The University of Memphis, Memphis, TN, USA
| |
Collapse
|
114
|
Biala G, Staniak N. Varenicline and mecamylamine attenuate locomotor sensitization and cross-sensitization induced by nicotine and morphine in mice. Pharmacol Biochem Behav 2010; 96:141-7. [PMID: 20451547 DOI: 10.1016/j.pbb.2010.04.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 04/19/2010] [Accepted: 04/28/2010] [Indexed: 11/29/2022]
Abstract
The present study focused on the evaluation of behavioural sensitization and cross-sensitization induced by nicotine and morphine in mice. First, we revealed that after 9days of nicotine administration (0.175mg/kg, free base), every other day and following its 7-day withdrawal, challenge doses of nicotine (0.175mg/kg) and morphine (5mg/kg) induced locomotor sensitization in mice. When we examined the influence of varenicline, a partial alpha4beta2 nicotinic receptor agonist (0.5, 1 and 2mg/kg) and mecamylamine (0.5, 1 and 2mg/kg), a non-selective nicotinic receptor antagonist, we found that both agents attenuated the acquisition and expression of nicotine sensitization as well as locomotor cross-sensitization between nicotine and morphine. Our results indicate similar cholinergic mechanisms involved in the locomotor stimulant effects of nicotine and morphine in mice, and as such these data may suggest that nicotinic neurotransmission could be a potential target for developing pharmacotherapeutic strategies to treat and prevent nicotine and/or opioid addiction.
Collapse
Affiliation(s)
- Grazyna Biala
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, 4 Staszica Street, 20-081 Lublin, Poland.
| | | |
Collapse
|
115
|
Gotti C, Guiducci S, Tedesco V, Corbioli S, Zanetti L, Moretti M, Zanardi A, Rimondini R, Mugnaini M, Clementi F, Chiamulera C, Zoli M. Nicotinic acetylcholine receptors in the mesolimbic pathway: primary role of ventral tegmental area alpha6beta2* receptors in mediating systemic nicotine effects on dopamine release, locomotion, and reinforcement. J Neurosci 2010; 30:5311-25. [PMID: 20392953 PMCID: PMC6632743 DOI: 10.1523/jneurosci.5095-09.2010] [Citation(s) in RCA: 188] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 03/02/2010] [Accepted: 03/08/2010] [Indexed: 01/14/2023] Open
Abstract
alpha6* nicotinic acetylcholine receptors (nAChRs) are highly and selectively expressed by mesostriatal dopamine (DA) neurons. These neurons are thought to mediate several behavioral effects of nicotine, including locomotion, habit learning, and reinforcement. Yet the functional role of alpha6* nAChRs in midbrain DA neurons is mostly unknown. The aim of this study was to determine the composition and in vivo functional role of alpha6* nAChR in mesolimbic DA neurons of male rats. Immunoprecipitation and immunopurification techniques coupled with cell-specific lesions showed that the composition of alpha6* nAChR in the mesostriatal system is heterogeneous, with (non-alpha4)alpha6beta2* being predominant in the mesolimbic pathway and alpha4alpha6beta2* in the nigrostriatal pathway. We verified whether alpha6* receptors mediate the systemic effects of nicotine on the mesolimbic DA pathway by perfusing the selective antagonists alpha-conotoxin MII (CntxMII) (alpha3/alpha6beta2* selective) or alpha-conotoxin PIA (CntxPIA) (alpha6beta2* selective) into ventral tegmental area (VTA). The intra-VTA perfusion of CntxMII or CntxPIA markedly decreased systemic nicotine-elicited DA release in the nucleus accumbens and habituated locomotion; the intra-VTA perfusion of CntxMII also decreased the rate of nicotine infusion in the maintenance phase of nicotine, but not of food, self-administration. Overall, the results of these experiments show that the alpha6beta2* nAChRs expressed in the VTA are necessary for the effects of systemic nicotine on DA neuron activity and DA-dependent behaviors such as locomotion and reinforcement, and suggest that alpha6beta2*-selective compounds capable of crossing the blood-brain barrier may affect the addictive properties of nicotine and therefore be useful in the treatment of tobacco dependence.
Collapse
Affiliation(s)
- Cecilia Gotti
- Consiglio Nazionale delle Ricerche, Institute of Neuroscience, Cellular and Molecular Pharmacology Center, Department of Medical Pharmacology, University of Milan, 20129 Milan, Italy
| | - Stefania Guiducci
- Department of Biomedical Sciences, Section of Physiology, University of Modena and Reggio Emilia, and
| | - Vincenzo Tedesco
- Neuropsychopharmacology Laboratory, Section of Pharmacology, Department of Medicine and Public Health, University of Verona, 37134 Verona, Italy
| | | | - Lara Zanetti
- Department of Biomedical Sciences, Section of Physiology, University of Modena and Reggio Emilia, and
| | - Milena Moretti
- Consiglio Nazionale delle Ricerche, Institute of Neuroscience, Cellular and Molecular Pharmacology Center, Department of Medical Pharmacology, University of Milan, 20129 Milan, Italy
| | - Alessio Zanardi
- Department of Biomedical Sciences, Section of Physiology, University of Modena and Reggio Emilia, and
| | - Roberto Rimondini
- Department of Pharmacology, University of Bologna, 40126 Bologna, Italy
| | - Manolo Mugnaini
- Addiction and Sleep Disorders Discovery Performance Unit, Neurosciences Center of Excellence for Drug Discovery, GlaxoSmithKline Medicines Research Center, 37135 Verona, Italy, and
| | - Francesco Clementi
- Consiglio Nazionale delle Ricerche, Institute of Neuroscience, Cellular and Molecular Pharmacology Center, Department of Medical Pharmacology, University of Milan, 20129 Milan, Italy
| | - Christian Chiamulera
- Neuropsychopharmacology Laboratory, Section of Pharmacology, Department of Medicine and Public Health, University of Verona, 37134 Verona, Italy
| | - Michele Zoli
- Department of Biomedical Sciences, Section of Physiology, University of Modena and Reggio Emilia, and
- Centro AntiFumo (Interdipartimentale), Azienda Ospedaliero–Universitaria Policlinico di Modena, 41100 Modena, Italy
| |
Collapse
|
116
|
Abstract
Alcohol intake at levels posing an acute heath risk is common amongst teenagers. Alcohol abuse is the second most common mental disorder worldwide. The incidence of smoking is decreasing in the Western world but increasing in developing countries and is the leading cause of preventable death worldwide. Considering the longstanding history of alcohol and tobacco consumption in human societies, it might be surprising that the molecular mechanisms underlying alcohol and smoking dependence are still incompletely understood. Effective treatments against the risk of relapse are lacking. Drugs of abuse exert their effect manipulating the dopaminergic mesocorticolimbic system. In this brain region, alcohol has many potential targets including membranes and several ion channels, while other drugs, for example nicotine, act via specific receptors or binding proteins. Repeated consumption of drugs of abuse mediates adaptive changes within this region, resulting in addiction. The high incidence of alcohol and nicotine co-abuse complicates analysis of the molecular basis of the disease. Gene expression profiling is a useful approach to explore novel drug targets in the brain. Several groups have utilised this technology to reveal drug-sensitive pathways in the mesocorticolimbic system of animal models and in human subjects. These studies are the focus of the present review.
Collapse
|
117
|
Grieder TE, Sellings LH, Vargas-Perez H, Ting-A-Kee R, Siu EC, Tyndale RF, van der Kooy D. Dopaminergic signaling mediates the motivational response underlying the opponent process to chronic but not acute nicotine. Neuropsychopharmacology 2010; 35:943-54. [PMID: 20032966 PMCID: PMC3055371 DOI: 10.1038/npp.2009.198] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mesolimbic dopamine (DA) system is implicated in the processing of the positive reinforcing effect of all drugs of abuse, including nicotine. It has been suggested that the dopaminergic system is also involved in the aversive motivational response to drug withdrawal, particularly for opiates, however, the role for dopaminergic signaling in the processing of the negative motivational properties of nicotine withdrawal is largely unknown. We hypothesized that signaling at dopaminergic receptors mediates chronic nicotine withdrawal aversions and that dopaminergic signaling would differentially mediate acute vs dependent nicotine motivation. We report that nicotine-dependent rats and mice showed conditioned place aversions to an environment paired with abstinence from chronic nicotine that were blocked by the DA receptor antagonist alpha-flupenthixol (alpha-flu) and in DA D(2) receptor knockout mice. Conversely, alpha-flu pretreatment had no effect on preferences for an environment paired with abstinence from acute nicotine. Taken together, these results suggest that dopaminergic signaling is necessary for the opponent motivational response to nicotine in dependent, but not non-dependent, rodents. Further, signaling at the DA D(2) receptor is critical in mediating withdrawal aversions in nicotine-dependent animals. We suggest that the alleviation of nicotine withdrawal primarily may be driving nicotine motivation in dependent animals.
Collapse
Affiliation(s)
- Taryn E Grieder
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
| | - Laurie H Sellings
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, ON, Canada
| | - Hector Vargas-Perez
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, ON, Canada
| | - Ryan Ting-A-Kee
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Eric C Siu
- Center for Addiction and Mental Health and Department of Pharmacology, University of Toronto, Toronto, ON, Canada
| | - Rachel F Tyndale
- Center for Addiction and Mental Health and Department of Pharmacology, University of Toronto, Toronto, ON, Canada
| | - Derek van der Kooy
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada,Department of Medical Genetics and Microbiology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
118
|
Shin R, Cao J, Webb SM, Ikemoto S. Amphetamine administration into the ventral striatum facilitates behavioral interaction with unconditioned visual signals in rats. PLoS One 2010; 5:e8741. [PMID: 20090902 PMCID: PMC2806927 DOI: 10.1371/journal.pone.0008741] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 12/24/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Administration of psychomotor stimulants like amphetamine facilitates behavior in the presence of incentive distal stimuli, which have acquired the motivational properties of primary rewards through associative learning. This facilitation appears to be mediated by the mesolimbic dopamine system, which may also be involved in facilitating behavior in the presence of distal stimuli that have not been previously paired with primary rewards. However, it is unclear whether psychomotor stimulants facilitate behavioral interaction with unconditioned distal stimuli. PRINCIPAL FINDINGS We found that noncontingent administration of amphetamine into subregions of the rat ventral striatum, particularly in the vicinity of the medial olfactory tubercle, facilitates lever pressing followed by visual signals that had not been paired with primary rewards. Noncontingent administration of amphetamine failed to facilitate lever pressing when it was followed by either tones or delayed presentation or absence of visual signals, suggesting that visual signals are key for enhanced behavioral interaction. Systemic administration of amphetamine markedly increased locomotor activity, but did not necessarily increase lever pressing rewarded by visual signals, suggesting that lever pressing is not a byproduct of heightened locomotor activity. Lever pressing facilitated by amphetamine was reduced by co-administration of the dopamine receptor antagonists SCH 23390 (D1 selective) or sulpiride (D2 selective). CONCLUSIONS Our results suggest that amphetamine administration into the ventral striatum, particularly in the vicinity of the medial olfactory tubercle, activates dopaminergic mechanisms that strongly enhance behavioral interaction with unconditioned visual stimuli.
Collapse
Affiliation(s)
- Rick Shin
- Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, United States Department of Health and Human Services, Baltimore, Maryland, United States of America
| | - Junran Cao
- Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, United States Department of Health and Human Services, Baltimore, Maryland, United States of America
| | - Sierra M. Webb
- Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, United States Department of Health and Human Services, Baltimore, Maryland, United States of America
| | - Satoshi Ikemoto
- Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, United States Department of Health and Human Services, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
119
|
Abstract
Neurobiologische Modelle der Substanzabhängigkeit postulieren, dass Abhängigkeit aus einem Zusammenspiel zwischen positiver und negativer Verstärkung entsteht. Die positive Verstärkung wird über die dopaminerge Transmission im Striatum vermittelt, während die negative Verstärkung die neurobiologischen Stresssysteme involviert. Abhängigkeit geht mit lang anhaltenden Änderungen der zerebralen Motivationssysteme einher. Neuropsychologische Forschungsarbeiten weisen auf ein beeinträchtigtes Entscheidungsverhalten hin, welches mit einer Dysfunktion im ventromedialen präfrontalen Kortex zusammenhängen könnte. Sie betonen die Rolle der Insula, welche die neuronale Grundlage für die fehlende Einsicht ins problematische Suchtverhalten als auch für die Vermittlung des bewussten Drangs, die Substanz zu konsumieren, sein könnte. Neurobiologische und neuropsychologische Sichtweisen werden in einem Modell integriert, das impulsive subkortikale und dopamin-bezogene Prozesse mit einer Beeinträchtigung der kortikalen Hemmung und kognitiven Defiziten verbindet.
Collapse
Affiliation(s)
- C. Martin-Soelch
- Klinik für Psychiatrie und Psychotherapie, Universitätsspital Zürich
| |
Collapse
|
120
|
|
121
|
Ishibashi M, Leonard CS, Kohlmeier KA. Nicotinic activation of laterodorsal tegmental neurons: implications for addiction to nicotine. Neuropsychopharmacology 2009; 34:2529-47. [PMID: 19625996 PMCID: PMC2762000 DOI: 10.1038/npp.2009.82] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Identifying the neurological mechanisms underlying nicotine reinforcement is a healthcare imperative, if society is to effectively combat tobacco addiction. The majority of studies of the neurobiology of addiction have focused on dopamine (DA)-containing neurons of the ventral tegmental area (VTA). However, recent data suggest that neurons of the laterodorsal tegmental (LDT) nucleus, which sends cholinergic, GABAergic, and glutamatergic-containing projections to DA-containing neurons of the VTA, are critical to gating normal functioning of this nucleus. The actions of nicotine on LDT neurons are unknown. We addressed this issue by examining the effects of nicotine on identified cholinergic and non-cholinergic LDT neurons using whole-cell patch clamp and Ca(2+)-imaging methods in brain slices from mice (P12-P45). Nicotine applied by puffer pipette or bath superfusion elicited membrane depolarization that often induced firing and TTX-resistant inward currents. Nicotine also enhanced sensitivity to injected current; and, baseline changes in intracellular calcium were elicited in the dendrites of some cholinergic LDT cells. In addition, activity-dependent calcium transients were increased, suggesting that nicotine exposure sufficient to induce firing may lead to enhancement of levels of intracellular calcium. Nicotine also had strong actions on glutamate and GABA-releasing presynaptic terminals, as it greatly increased the frequency of miniature EPSCs and IPSCs to both cholinergic and non-cholinergic neurons. Utilization of nicotinic acetylcholine receptors (nAChR) subunit antagonists revealed that presynaptic, inhibitory terminals on cholinergic neurons were activated by receptors containing alpha 7, beta2, and non-alpha 7 subunits, whereas, presynaptic glutamatergic terminals were activated by nAChRs that comprised non-alpha 7 subunits. We also found that direct nicotinic actions on cholinergic LDT neurons were mediated by receptors containing alpha 7, beta2, and non-alpha 7 subunits. These findings led us to suggest that nicotine exposure from smoking will enhance both the excitability and synaptic modulation of cholinergic and non-cholinergic LDT neurons, and increase their signature neurotransmitter outflow to target regions, including the VTA. This may reinforce the direct actions of this drug within reward circuitry and contribute to encoding stimulus saliency.
Collapse
Affiliation(s)
- Masaru Ishibashi
- Department of Physiology, New York Medical College, Valhalla, NY 10595 USA
| | | | - Kristi A. Kohlmeier
- Department of Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark,Author to whom correspondence should be addressed: Kristi A. Kohlmeier, Department of Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark, Phone: +45 35 33 60 07, FAX: +45 35 30 60 20, e-mail:
| |
Collapse
|
122
|
Zuo Y, Gilbert DG, Rabinovich NE, Riise H, Needham R, Huggenvik JI. DRD2-related TaqIA polymorphism modulates motivation to smoke. Nicotine Tob Res 2009; 11:1321-9. [PMID: 19819938 DOI: 10.1093/ntr/ntp141] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION TaqIA polymorphism, a genetic variant associated with the expression level of dopamine D2 receptors in the brain, has been linked to various aspects of smoking behavior, including smoking prevalence, affective withdrawal symptoms, and smoking cessation outcome. However, its involvement in motivation to smoke cigarettes has not been elucidated. METHODS The present study examined the possible differences in self-reported reasons to smoke and craving for smoking in 160 smokers participating in a clinical trial. RESULTS Individuals with at least one A1 allele of the TaqIA polymorphism were more likely to report smoking for stimulating effects and to reduce negative affect compared with those lacking an A1 allele. The association of the A1 genotype with a higher probability and stronger motive to smoker to enhance cognitive functioning was evident in female but not in male smokers. Female A1 carriers also expected a greater likelihood of smoking for pleasure than those without an A1 allele. A1 subjects reported stronger craving for cigarettes during early days and the last phase of a 6-week abstinence period. DISCUSSION These results support the idea that dopaminergic transmission plays an important role in the neurobiological basis of reasons for smoking and that the TaqIA variant is one of the genetic factors underlying individual differences in these aspects. These findings also have implications for improving treatment strategies to help individuals quit smoking by controlling their motivation to continue cigarette consumption.
Collapse
Affiliation(s)
- Yantao Zuo
- Department of Psychology, Southern Illinois University-Carbondale, IL, USA
| | | | | | | | | | | |
Collapse
|
123
|
Tan H, Bishop SF, Lauzon NM, Sun N, Laviolette SR. Chronic nicotine exposure switches the functional role of mesolimbic dopamine transmission in the processing of nicotine's rewarding and aversive effects. Neuropharmacology 2009; 56:741-51. [PMID: 19133278 DOI: 10.1016/j.neuropharm.2008.12.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 12/09/2008] [Accepted: 12/14/2008] [Indexed: 11/30/2022]
Abstract
The mammalian ventral tegmental area (VTA) and associated mesolimbic dopamine (DA) system are critical neural substrates for processing nicotine's motivational effects. Considerable evidence suggests that the role of DA transmission may be altered as a function of nicotine exposure. Using a combination of in vivo neuronal recording and behavioral conditioning, we report that chronic nicotine exposure induces a functional switch in the role of mesolimbic DA transmission. Thus, in nicotine-naive subjects, blockade of DA transmission potentiates the rewarding effects of sub-reward-threshold doses of nicotine and reverses the motivational valence of nicotine from aversive to rewarding. However, in animals treated chronically with nicotine, DA blockade switches previously sub-reward-threshold or rewarding doses of nicotine into aversion signals. Neuronal VTA recordings similarly revealed a functional switch in this DAergic neuronal circuit resulting in strongly increased sensitivity of the VTA DAergic system to nicotine administration and a tonic reduction in the baseline activity of VTA DAergic neurons. These results demonstrate a functional switch in the role of DAergic transmission during the acute versus chronic phases of nicotine exposure and suggest that mesolimbic DA transmission plays qualitatively distinct roles in the processing of nicotine's motivational effects as a function of drug exposure.
Collapse
Affiliation(s)
- Huibing Tan
- Dept. of Anatomy & Cell Biology, The Schulich School of Medicine, University of Western Ontario, London, Ontario, Canada N6A 5C1
| | | | | | | | | |
Collapse
|
124
|
Corrigall WA. Hypocretin mechanisms in nicotine addiction: evidence and speculation. Psychopharmacology (Berl) 2009; 206:23-37. [PMID: 19529922 DOI: 10.1007/s00213-009-1588-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 06/01/2009] [Indexed: 01/11/2023]
Abstract
BACKGROUND The hypocretin/orexin system has been implicated in arousal mechanisms, sleep, and sleep disorders, including narcolepsy, and more recently in drug addiction. Theoretically, hypocretin (hcrt) mechanisms appear to be potential substrates for nicotine addiction: arousal and attentional mechanisms influence use and withdrawal symptoms, and hcrt systems overlap anatomically with a number of brain regions associated with nicotine addiction. OBJECTIVE This review summarizes the studies that have examined hcrt mechanisms in the effects of nicotine and describes hcrt innervation of, and effects in, several brain regions implicated in nicotine addiction. The review speculates on the possible mechanisms by which hcrt may contribute to nicotine addiction in these regions, with the objective of encouraging research in this area. RESULTS In a small literature, both experimenter-administered and self-administered nicotine have been shown to elicit or depend on hcrt signaling. However, although untested in experimental designs, there is compelling evidence that hcrt mechanisms in the ventral tegmental area, the pontine region, thalamocortical circuits, the prefrontal cortex, and the amygdala could have a broad influence on nicotine addiction. CONCLUSIONS Evidence reviewed leads to the conclusion that hcrt mechanisms could mediate several dimensions of nicotine addiction, including a multi-faceted regulation of mesocorticolimbic dopaminergic function, but beyond dopaminergic mechanisms, hcrt could influence nicotine use and relapse during abstinence through broadly based arousal/attentional effects. These speculative ideas need to be examined experimentally; the potential gains are a more thorough understanding of the pathophysiology of nicotine addiction, and the discovery of novel targets for the development of pharmacotherapeutics.
Collapse
|
125
|
The neuropharmacological substrates of nicotine reward: reinforcing versus reinforcement-enhancing effects of nicotine. Behav Pharmacol 2009; 20:211-25. [PMID: 19421028 DOI: 10.1097/fbp.0b013e32832c7083] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Compulsive nicotine use is thought to be maintained by the acute reinforcing effects of nicotine and the reinforcement-enhancing effects of nicotine, in addition to the negative consequences of nicotine abstinence. Nicotine self-administration and nicotine-induced enhancement of non-nicotine reinforcers such as intracranial self-stimulation provide measures of these dual rewarding properties of nicotine. First, pharmacological manipulations that modulate the reinforcing and reinforcement-enhancing effects of nicotine are identified and discussed. Second, the interpretation and implications of data that identified shared and specific pharmacological substrates underlying the dual rewarding effects of nicotine are discussed, including implications for the preclinical testing of putative antismoking medications. In conclusion, reinforcement-related behaviors that are mediated by central reinforcement processes are likely to, and generally do, exhibit a number of common pharmacological substrates. Interestingly, however, a few pharmacological classes of compounds seem to exert selective effects on components of the dual nicotine reward mechanisms, indicating differences in the pharmacological substrates of the reinforcing and reinforcement-enhancing effects of nicotine. Further characterization of such compounds may ultimately lead to the identification of novel medications for nicotine dependence in humans.
Collapse
|
126
|
Lupica CR, Riegel AC. Endocannabinoid release from midbrain dopamine neurons: a potential substrate for cannabinoid receptor antagonist treatment of addiction. Neuropharmacology 2009; 48:1105-16. [PMID: 15878779 DOI: 10.1016/j.neuropharm.2005.03.016] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 02/18/2005] [Accepted: 03/09/2005] [Indexed: 11/30/2022]
Abstract
Substantial evidence suggests that all commonly abused drugs act upon the brain reward circuitry to ultimately increase extracellular concentrations of the neurotransmitter dopamine in the nucleus accumbens and other forebrain areas. Many drugs of abuse appear to increase dopamine levels by dramatically increase the firing and bursting rates of dopamine neurons located in the ventral mesencephalon. Recent clinical evidence in humans and behavioral evidence in animals indicate that cannabinoid receptor antagonists such as SR141716A (Rimonabant) can reduce the self-administration of, and craving for, several commonly addictive drugs. However, the mechanism of this potentially beneficial effect has not yet been identified. We propose, on the basis of recent studies in our laboratory and others, that these antagonists may act by blocking the effects of endogenously released cannabinoid molecules (endocannabinoids) that are released in an activity- and calcium-dependent manner from mesencephalic dopamine neurons. It is hypothesized that, through the antagonism of cannabinoid CB1 receptors located on inhibitory and excitatory axon terminals targeting the midbrain dopamine neurons, the effects of the endocannabinoids are occluded. The data from these studies therefore suggest that the endocannabinoid system and the CB1 receptors located in the ventral mesencephalon may play an important role in regulating drug reward processes, and that this substrate is recruited whenever dopamine neuron activity is increased.
Collapse
Affiliation(s)
- Carl R Lupica
- Cellular Neurobiology Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, U.S. Department of Health and Human Services, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.
| | | |
Collapse
|
127
|
Individual differences in response to novelty and the conditioned locomotor effects of nicotine. Behav Pharmacol 2009; 20:322-9. [DOI: 10.1097/fbp.0b013e32832f0176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
128
|
Govind AP, Vezina P, Green WN. Nicotine-induced upregulation of nicotinic receptors: underlying mechanisms and relevance to nicotine addiction. Biochem Pharmacol 2009; 78:756-65. [PMID: 19540212 DOI: 10.1016/j.bcp.2009.06.011] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 06/04/2009] [Accepted: 06/09/2009] [Indexed: 02/05/2023]
Abstract
A major hurdle in defining the molecular biology of nicotine addiction has been characterizing the different nicotinic acetylcholine receptor (nAChR) subtypes in the brain and how nicotine alters their function. Mounting evidence suggests that the addictive effects of nicotine, like other drugs of abuse, occur through interactions with its receptors in the mesolimbic dopamine system, particularly ventral tegmental area (VTA) neurons, where nicotinic receptors act to modulate the release of dopamine. The molecular identity of the nicotinic receptors responsible for drug seeking behavior, their cellular and subcellular location and the mechanisms by which these receptors initiate and maintain addiction are poorly defined. In this commentary, we review how nicotinic acetylcholine receptors (nAChRs) are upregulated by nicotine exposure, the potential posttranslational events that appear to cause it and how upregulation is linked to nicotine addiction.
Collapse
Affiliation(s)
- Anitha P Govind
- Department of Neurobiology, University of Chicago, Abbot Hall 402-MC0926, Chicago, IL 60637, USA.
| | | | | |
Collapse
|
129
|
Domino EF, Tsukada H, Harada N. Positron emission tomographic measure of brain dopamine dependence to nicotine as a model of drugs of abuse. Psychopharmacology (Berl) 2009; 204:149-53. [PMID: 19137279 DOI: 10.1007/s00213-008-1445-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 12/17/2008] [Indexed: 11/27/2022]
Abstract
RATIONALE Nicotine/tobacco are prototypic substances used throughout the world. Nicotine abstinence produces some depressive-like effects which are treated by the dopamine (DA) and norepinephrine reuptake inhibitor bupropion. A quantitative measure of the regional brain utilization of these catecholamines (CA) during nicotine dependence and withdrawal is important. OBJECTIVE The aim of this study was to prove that regional brain DA utilization by nicotine can be quantified by positron emission tomography (PET) using L-[beta-(11)C]DOPA. MATERIALS AND METHODS Eight young Macaca mulatta monkeys were given 0.9% NaCl or nicotine in doses of 32 or 100 microg/kg i.m. bid for 9 days to produce minimal dependence. On the tenth day, PET measurements were repeated before and after i.v. nicotine administration. PET studies were done in habituated, trained, and fully conscious animals. RESULTS Compared to a 0.9% NaCl control, acute i.v. nicotine as a bolus plus infusion for 30 min in similar doses to maintain a steady-state level for 30 min did not affect the utilization rate constant (k (3)) in dorsal or ventral striatum as measured by L-[beta-(11)C]DOPA. When monkeys were given nicotine bid repeatedly after overnight nicotine abstinence, CA utilization was reduced. A subsequent nicotine dose normalized utilization to slightly above control levels. Changes in ventral striatum were similar to those in dorsal striatum. The reduced rate of utilization demonstrated with L-[beta-(11)C]DOPA after overnight nicotine abstinence and its reversal by nicotine the next day provides an important PET measure of brain nicotine dependence and withdrawal. This method can be applied to other substances of abuse that release DA.
Collapse
Affiliation(s)
- Edward F Domino
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-0632, USA.
| | | | | |
Collapse
|
130
|
Subjective, cognitive/psychomotor, and physiological effects of aripiprazole in Chinese light and heavy smokers. Drug Alcohol Depend 2009; 101:42-52. [PMID: 19070440 DOI: 10.1016/j.drugalcdep.2008.10.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 10/27/2008] [Accepted: 10/29/2008] [Indexed: 11/20/2022]
Abstract
BACKGROUND Drug addiction researchers have begun to study dopamine partial agonists as potential therapeutic agents. The partial dopamine D(2) receptor agonist aripiprazole has recently been tested as a treatment for stimulant and alcohol dependence in both animal and clinical studies. METHODS A randomized and placebo-controlled pilot clinical study was conducted in a population of Chinese light and heavy smokers to assess the effect of aripiprazole on various responses to smoking. The primary outcomes were subject's ratings on questionnaires of smoking urge, withdrawal syndromes, and cigarette evaluation. Placebo, 5, and 10mg aripiprazole were acutely administered in all participants, with administrations at least 7 days apart. Subjective responses to a smoked cigarette, working memory, and attention/psychomotor performance were assessed before and after drug administration in each experimental session. Abstinence-induced smoking urge, withdrawal symptoms, blood pressure, and heart rate were also measured every 45 min after drug administration. Finally, a cue-testing session was carried out 4h after each drug administration. RESULTS Administration of 10mg aripiprazole significantly decreased both the subjective response and psychological reward derived from smoking a cigarette in heavy smokers. While neither 5 nor 10mg aripiprazole significantly decreased abstinence-induced smoking urges or withdrawal symptoms in light and heavy smokers, these doses substantially attenuated drug cue-induced smoking urges in heavy smokers. Aripiprazole did not affect working memory or attention/psychomotor performance. CONCLUSIONS Light and heavy smokers responded differently to aripiprazole across various dependent measures. Aripiprazole may potentially affect various subjective responses to smoking in heavy smokers.
Collapse
|
131
|
D'hoedt D, Bertrand D. Nicotinic acetylcholine receptors: an overview on drug discovery. Expert Opin Ther Targets 2009; 13:395-411. [DOI: 10.1517/14728220902841045] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
132
|
Domino EF, Tsukada H. Nicotine sensitization of monkey striatal dopamine release. Eur J Pharmacol 2009; 607:91-5. [PMID: 19232339 DOI: 10.1016/j.ejphar.2009.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 01/20/2009] [Accepted: 02/09/2009] [Indexed: 11/26/2022]
Abstract
This study with monkeys was designed to answer two questions. 1) Does acute nicotine preferentially release more dopamine in the striatum than in the prefrontal cortex? 2) Do repeated doses of nicotine produce sensitization of striatal dopamine release? Microdialysis techniques were used to measure extracellular dopamine in both brain regions in two separate groups of conscious animals. The acute nicotine i.v. dose schedule was a bolus of 32 microg/kg plus an infusion of +/-0.8 microg/kg/min and a 100 microg/kg bolus plus an infusion of +/-2.53 microg/kg/min for 30 min to mimic human tobacco smoking arterial plasma nicotine concentrations. Acute nicotine given i.v. released more dopamine in the striatum than in the prefrontal cortex. In the second experiment, for convenience, daily nicotine was given i.m. and not i.v. bid in doses of 32 or 100 microg/kg for nine days. Dopamine release was measured after overnight nicotine abstinence using the i.v. dose schedule from the first experiment. Baseline dopamine release was significantly reduced (77.6% of control, P<0.05). With a lowered baseline, a greater facilitation of dopamine release was produced by nicotine compared to that obtained under control conditions when the baseline was higher. The impaired dopamine release with overnight nicotine abstinence was transiently enhanced in a dose dependent manner. These data regarding the striatum are consistent with previous findings in rodents of nicotine sensitization of dopamine release especially in nucleus accumbens following repeated administration.
Collapse
Affiliation(s)
- Edward F Domino
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Shizuoka 484-6601, Japan.
| | | |
Collapse
|
133
|
Hayes DJ, Mosher TM, Greenshaw AJ. Differential effects of 5-HT2C receptor activation by WAY 161503 on nicotine-induced place conditioning and locomotor activity in rats. Behav Brain Res 2009; 197:323-30. [DOI: 10.1016/j.bbr.2008.08.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Revised: 08/21/2008] [Accepted: 08/26/2008] [Indexed: 10/21/2022]
|
134
|
Abstract
Accumulating evidence suggests that the antecedents, consequences, and mechanisms of drug abuse and dependence are not identical in males and females and that gender may be an important variable in treatment and prevention. Although there has been a decline in smoking prevalence in developed countries, females are less successful in quitting. Tobacco use is accepted to be a form of addiction, which manifests sex differences. There is also evidence for sex differences in the central effects of nicotine in laboratory animals. Although social factors impact smoking substantially in humans, findings from nonhuman subjects in controlled experiments provide support that sex differences in nicotine/tobacco addiction have a biological basis. Differences in the pharmacokinetic properties of nicotine or the effect of gonadal hormones may underlie some but not all sex differences observed. Laboratory-based information is very important in developing treatment strategies. Literature findings suggest that including sex as a factor in nicotine/tobacco-related studies will improve our success rates in individually tailored smoking cessation programs.
Collapse
Affiliation(s)
- Sakire Pogun
- Ege University Center for Brain Research, Ege University, Bornova, Izmir, 35100, Turkey.
| | | |
Collapse
|
135
|
Abstract
While most cigarette smokers endorse a desire to quit smoking, only 14-49% will achieve abstinence after 6 months or more of treatment. A greater understanding of the effects of smoking on brain function may result in improved pharmacological and behavioral interventions for this condition. Research groups have examined the effects of acute and chronic nicotine/cigarette exposure on brain activity using functional imaging; the purpose of this chapter is to synthesize findings from such studies and present a coherent model of brain function in smokers. Responses to acute administration of nicotine/smoking include reduced global brain activity; activation of the prefrontal cortex, thalamus, and visual system; activation of the thalamus and visual cortex during visual cognitive tasks; and increased dopamine (DA) concentration in the ventral striatum/nucleus accumbens. Responses to chronic nicotine/cigarette exposure include decreased monoamine oxidase (MAO) A and B activity in the basal ganglia and a reduction in alpha4beta2 nicotinic acetylcholine receptor (nAChR) availability in the thalamus and putamen (accompanied by an overall upregulation of these receptors). These findings indicate that smoking enhances neurotransmission through cortico-basal ganglia-thalamic circuits by direct stimulation of nAChRs, indirect stimulation via DA release or MAO inhibition, or a combination of these and possibly other factors. Activation of this circuitry may be responsible for the effects of smoking seen in tobacco-dependent smokers, such as improvements in attentional performance, mood, anxiety, and irritability.
Collapse
Affiliation(s)
- Anil Sharma
- Department of Psychiatry and Biobehavioral Sciences, UCLA School of Medicine, Greater Los Angeles VA Healthcare System, 11301 Wilshire Blvd. Bldg 256 Suite 221, Los Angeles, CA 90073, USA.
| | | |
Collapse
|
136
|
Rahman S, Zhang Z, Papke RL, Crooks PA, Dwoskin LP, Bardo MT. Region-specific effects of N
,N
′-dodecane-1,12-diyl-bis-3-picolinium dibromide on nicotine-induced increase in extracellular dopamine in vivo. Br J Pharmacol 2009. [DOI: https://doi.org/10.1038/sj.bjp.0707612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
137
|
Alburges ME, Frankel PS, Hoonakker AJ, Hanson GR. Responses of limbic and extrapyramidal substance P systems to nicotine treatment. Psychopharmacology (Berl) 2009; 201:517-27. [PMID: 18773198 PMCID: PMC2678878 DOI: 10.1007/s00213-008-1316-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 08/21/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE Neuropeptides are linked to the psychopathology of stimulants of abuse, principally through dopamine mechanisms. Substance P (SP) is one of these neuropeptides and is associated with both limbic and extrapyramidal dopaminergic pathways and likely contributes to the pharmacology of these stimulants. The effects of nicotine on these dopamine systems have also been extensively studied; however, its effects on the associated SP pathways have received little attention. OBJECTIVES In the present study, we elucidated the effects of nicotine treatment on limbic and extrapyramidal SP systems by measuring changes in associated SP tissue concentrations. MATERIALS AND METHODS Male Sprague-Dawley rats received (+/-)nicotine 4.0 mg/kg/day (0.8 mg/kg, intraperitoneally; five injections at 2-h intervals) in the presence or absence of selective dopamine D1 and D2 receptor antagonists or a nonselective nicotinic acetylcholine receptor antagonist. RESULTS The nicotine treatment significantly but temporarily decreased substance P-like immunoreactivity (SPLI) content in the ventral tegmental area (VTA) and substantia nigra 12-18 h after drug exposure. The nicotine-mediated changes in SPLI were selectively blocked by pretreatment with mecamylamine as well as a dopamine D1, D2, or both receptor antagonists. Other brain areas that also selectively demonstrated nicotine-related declines in SPLI content included prefrontal cortex, the nucleus accumbens shell, and the very posterior caudate. CONCLUSIONS These findings indicate that some limbic and basal ganglia SP systems are significantly affected by exposure to nicotine through processes mediated by nicotinic and dopaminergic receptors, suggesting a role for SP pathways in nicotine's limbic and extrapyramidal effects.
Collapse
Affiliation(s)
- Mario E Alburges
- Department of Pharmacology and Toxicology, University of Utah, 30 South 2000 East, Room 201, Salt Lake City, UT, USA.
| | | | | | | |
Collapse
|
138
|
Significant association of ANKK1 and detection of a functional polymorphism with nicotine dependence in an African-American sample. Neuropsychopharmacology 2009; 34:319-30. [PMID: 18354387 DOI: 10.1038/npp.2008.37] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The dopaminergic system in the brain plays a critical role in nicotine addiction. Genetic variants in the dopaminergic system, including those in dopamine receptor genes, represent plausible candidates for the genetic study of nicotine dependence (ND). We investigated various polymorphisms in the dopamine D(2) receptor gene (DRD2) and its neighboring ankyrin repeats and kinase domain containing 1 gene (ANKK1) to determine whether they were associated with ND. We examined 16 single nucleotide polymorphisms (SNPs) at DRD2 and 7 SNPs at ANKK1 in our Mid-South Tobacco Family cohort, which consisted of 2037 participants representing two distinct American populations. Several SNPs (rs7131056, rs4274224, rs4648318, and rs6278) in DRD2, along with the Taq IA polymorphism (rs1800497) in ANKK1, revealed initial significant associations with ND in European Americans, but not after correction for multiple testing, indicating a weak association of DRD2 with ND. In contrast, associations for ANKK1 with ND in the African-American and pooled samples, specifically for SNP rs2734849, remained significant after correction. With a non-synonymous G to A transition, rs2734849 produces an amino-acid change (arginine to histidine) in C-terminal ankyrin repeat domain of ANKK1. Using the luciferase reporter assay, we further demonstrated that the variant alters expression level of NF-kappaB-regulated genes. Since DRD2 expression is regulated by transcription factor NF-kappaB, we suspect that rs2734849 may indirectly affect dopamine D(2) receptor density. We conclude that ANKK1 is associated with ND and polymorphism rs2734849 in ANKK1 represents a functional causative variant for ND in African-American smokers.
Collapse
|
139
|
Rahman S, Neugebauer NM, Zhang Z, Crooks PA, Dwoskin LP, Bardo MT. The novel nicotinic receptor antagonist N,N′-dodecane-1,12-diyl-bis-3-picolinium dibromide decreases nicotine-induced dopamine metabolism in rat nucleus accumbens. Eur J Pharmacol 2008. [DOI: https://doi.org/10.1016/j.ejphar.2008.10.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
140
|
Yang K, Hu J, Lucero L, Liu Q, Zheng C, Zhen X, Jin G, Lukas RJ, Wu J. Distinctive nicotinic acetylcholine receptor functional phenotypes of rat ventral tegmental area dopaminergic neurons. J Physiol 2008; 587:345-61. [PMID: 19047205 DOI: 10.1113/jphysiol.2008.162743] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Dopaminergic (DAergic) neuronal activity in the ventral tegmental area (VTA) is thought to contribute generally to pleasure, reward, and drug reinforcement and has been implicated in nicotine dependence. nAChRs expressed in the VTA exhibit diverse subunit compositions, but the functional and pharmacological properties are largely unknown. Here, using patch-clamp recordings in single DAergic neurons freshly dissociated from rat VTA, we clarified three functional subtypes of nAChRs (termed ID, IID and IIID receptors) based on whole-cell current kinetics and pharmacology. Kinetic analysis demonstrated that comparing to ID, IID receptor-mediated current had faster activation and decay constant and IIID receptor-mediated current had larger current density. Pharmacologically, ID receptor-mediated current was sensitive to the alpha4beta2-nAChR agonist RJR-2403 and antagonist dihydro-beta-erythroidine (DHbetaE); IID receptor-mediated current was sensitive to the selective alpha7-nAChR agonist choline and antagonist methyllycaconitine (MLA); while IIID receptor-mediated current was sensitive to the beta4-containing nAChR agonist cytisine and antagonist mecamylamine (MEC). The agonist concentration-response relationships demonstrated that IID receptor-mediated current exhibited the highest EC(50) value compared to ID and IIID receptors, suggesting a relatively low agonist affinity of type IID receptors. These results suggest that the type ID, IID and IIID nAChR-mediated currents are predominately mediated by activation of alpha4beta2-nAChR, alpha7-nAChR and a novel nAChR subtype(s), respectively. Collectively, these findings indicate that the VTA DAergic neurons express diversity and multiplicity of functional nAChR subtypes. Interestingly, each DAergic neuron predominantly expresses only one particularly functional nAChR subtype, which may have distinct but important roles in regulation of VTA DA neuronal function, DA transmission and nicotine dependence.
Collapse
Affiliation(s)
- Kechun Yang
- Division of Neurology, Barrow Neurological Institute, Phoenix, AZ 85013-4496, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
141
|
Cassaday HJ, Finger BC, Horsley RR. Methylphenidate and nicotine focus responding to an informative discrete CS over successive sessions of appetitive conditioning. J Psychopharmacol 2008; 22:849-59. [PMID: 18208930 DOI: 10.1177/0269881107083842] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Methylphenidate (MP) and nicotine would be expected to improve associative learning, though previous evidence suggests that they should reduce the selectivity with which associations are formed. Here we tested their effects on learning the association between a conditioned stimulus (CS) and food (unconditioned stimulus, UCS) in male Wistar rats. The UCS was delivered immediately (0 s) following CS offset or after a 10 s trace. In addition to the measures of discrete CS conditioning, contextual and trace responding was measured in the inter-trial- and the inter-stimulus-interval, respectively. In all cases, conditioning was measured as nose poking for food. Both MP and nicotine improved the acquisition of discrete cue conditioning. Acquisition was accelerated (compared to saline) under 5 but not 1 mg/kg MP and 0.6, but not 0.4 mg/kg nicotine. In each case, this effect was observed in 0 s but not 10 s conditioned groups. For comparison, some earlier published data obtained following the same procedure with D-amphetamine were re-analysed in the same way. Amphetamine similarly improved conditioning in the 0 s group, in this case at 0.5, but not 1.5 mg/kg. Thus three different dopamine agonists increased the ability to focus responding to CS presentations over successive sessions of appetitive acquisition.
Collapse
Affiliation(s)
- H J Cassaday
- School of Psychology, University of Nottingham, Nottingham, UK.
| | | | | |
Collapse
|
142
|
The novel nicotinic receptor antagonist N,N'-dodecane-1,12-diyl-bis-3-picolinium dibromide decreases nicotine-induced dopamine metabolism in rat nucleus accumbens. Eur J Pharmacol 2008; 601:103-5. [PMID: 19000671 DOI: 10.1016/j.ejphar.2008.10.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 09/30/2008] [Accepted: 10/10/2008] [Indexed: 11/22/2022]
Abstract
The current study examined the effect of the novel nicotinic acetylcholine receptor antagonist, N,N'-dodecane-1,12-diyl-bis-3-picolinium dibromide (bPiDDB), on nicotine-induced dopamine metabolism in rat nucleus accumbens, striatum and medial prefrontal cortex. Acute nicotine (0.5 mg/kg, s.c.) produced an increase in the content of dihydroxyphenylacetic acid (DOPAC) in nucleus accumbens, but not in striatum or medial prefrontal cortex. Pretreatment with bPiDDB (1 or 3 mg/kg, s.c.) dose-dependently inhibited the nicotine-induced increase in DOPAC content in nucleus accumbens. These results indicate that bPiDDB inhibits the nicotine-induced increase in DOPAC in reward-relevant brain region targeting nicotinic acetylcholine receptors.
Collapse
|
143
|
Huang W, Payne TJ, Ma JZ, Li MD. A functional polymorphism, rs6280, in DRD3 is significantly associated with nicotine dependence in European-American smokers. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:1109-15. [PMID: 18348205 DOI: 10.1002/ajmg.b.30731] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nicotine enhances reward functions in the mesocorticolimbic dopamine system in general and the nucleus accumbens in particular. The genes encoding dopamine receptors are thus plausible candidates for involvement in nicotine dependence (ND). We investigated 13 single nucleotide polymorphisms (SNPs) spanning a region of the dopamine D(3) receptor gene (DRD3) to determine whether DRD3 is associated with ND. We studied a set of 2,037 subjects in 602 nuclear families representing two distinct American populations using three ND measures, namely, smoking quantity (SQ), the Heaviness of Smoking Index (HSI), and the Fagerström Test for ND (FTND). In the family based association study, we found that SNP rs6280 showed a strong association with ND in European-Americans (EAs) and the pooled sample, whereas SNPs rs1486012 and rs963468 had weak associations with ND in African-Americans (AAs) and the pooled sample. Further haplotype analysis with all contiguous 3-SNP groups revealed relatively weak evidence for association of DRD3 with ND in the EA and pooled samples. The results indicate that DRD3 is significantly associated with ND in EAs, and that rs6280, a functional polymorphism causing an amino acid change of serine to glycine (Ser9Gly) in the N-terminal extracellular domain of the D(3) receptor, likely is causative of the association between DRD3 and ND.
Collapse
Affiliation(s)
- Weihua Huang
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia 22911, USA
| | | | | | | |
Collapse
|
144
|
You ZB, Wang B, Zitzman D, Wise RA. Acetylcholine release in the mesocorticolimbic dopamine system during cocaine seeking: conditioned and unconditioned contributions to reward and motivation. J Neurosci 2008; 28:9021-9. [PMID: 18768696 PMCID: PMC2562350 DOI: 10.1523/jneurosci.0694-08.2008] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 07/29/2008] [Accepted: 07/29/2008] [Indexed: 01/30/2023] Open
Abstract
Microdialysis was used to assess the contribution to cocaine seeking of cholinergic input to the mesocorticolimbic dopamine system in ventral tegmental area (VTA). VTA acetylcholine (ACh) was elevated in animals lever pressing for intravenous cocaine and in cocaine-experienced and cocaine-naive animals passively receiving similar "yoked" injections. In cocaine-trained animals, the elevations comprised an initial (first hour) peak to approximately 160% of baseline and a subsequent plateau of 140% of baseline for the rest of the cocaine intake period. In cocaine-naive animals, yoked cocaine injections raised ACh levels to the 140% plateau but did not cause the initial 160% peak. In cocaine-trained animals that received unexpected saline (extinction conditions) rather than the expected cocaine, the initial peak was seen but the subsequent plateau was absent. VTA ACh levels played a causal role and were not just a correlate of cocaine seeking. Blocking muscarinic input to the VTA increased cocaine intake; the increase in intake offset the decrease in cholinergic input, resulting in the same VTA dopamine levels as were seen in the absence of the ACh antagonists. Increased VTA ACh levels (resulting from 10 microM VTA neostigmine infusion) increased VTA dopamine levels and reinstated cocaine seeking in cocaine-trained animals that had undergone extinction; these effects were strongly attenuated by local infusion of a muscarinic antagonist and weakly attenuated by a nicotinic antagonist. These findings identify two cholinergic responses to cocaine self-administration, an unconditioned response to cocaine itself and a conditioned response triggered by cocaine-predictive cues, and confirm that these cholinergic responses contribute to the control of cocaine seeking.
Collapse
Affiliation(s)
- Zhi-Bing You
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland 21224, USA.
| | | | | | | |
Collapse
|
145
|
Fowler CD, Arends MA, Kenny PJ. Subtypes of nicotinic acetylcholine receptors in nicotine reward, dependence, and withdrawal: evidence from genetically modified mice. Behav Pharmacol 2008; 19:461-84. [PMID: 18690103 PMCID: PMC2669417 DOI: 10.1097/fbp.0b013e32830c360e] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) can regulate the activity of many neurotransmitter pathways throughout the central nervous system and are considered to be important modulators of cognition and emotion. nAChRs are also the primary site of action in the brain for nicotine, the major addictive component of tobacco smoke. nAChRs consist of five membrane-spanning subunits (alpha and beta isoforms) that can associate in various combinations to form functional nAChR ion channels. Owing to a dearth of nAChR subtype-selective ligands, the precise subunit composition of the nAChRs that regulate the rewarding effects of nicotine and the development of nicotine dependence are unknown. The advent of mice with genetic nAChR subunit modifications, however, has provided a useful experimental approach to assess the contribution of individual subunits in vivo. Here, we review data generated from nAChR subunit knockout and genetically modified mice supporting a role for discrete nAChR subunits in nicotine reinforcement and dependence processes. Importantly, the rates of tobacco dependence are far higher in patients suffering from comorbid psychiatric illnesses compared with the general population, which may at least partly reflect disease-associated alterations in nAChR signaling. An understanding of the role of nAChRs in psychiatric disorders associated with high rates of tobacco addiction, therefore, may reveal novel insights into mechanisms of nicotine dependence. Thus, we also briefly review data generated from genetically modified mice to support a role for discrete nAChR subunits in anxiety disorders, depression, and schizophrenia.
Collapse
Affiliation(s)
- Christie D. Fowler
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Michael A. Arends
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Paul J. Kenny
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| |
Collapse
|
146
|
Laviolette SR, Lauzon NM, Bishop SF, Sun N, Tan H. Dopamine signaling through D1-like versus D2-like receptors in the nucleus accumbens core versus shell differentially modulates nicotine reward sensitivity. J Neurosci 2008; 28:8025-33. [PMID: 18685027 PMCID: PMC6670771 DOI: 10.1523/jneurosci.1371-08.2008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 11/21/2022] Open
Abstract
Considerable evidence implicates the mesolimbic dopamine (DA) system in the processing of nicotine's reinforcing properties, specifically the ventral tegmental area (VTA) and the terminal fields of VTA DAergic projections to the "core" (NAcore) and "shell" (NAshell) subdivisions of the nucleus accumbens (NAc). However, the specific roles of DA D(1)-like and D(2)-like receptor subtypes in nicotine reward processing within these NAc subregions have not been elucidated. We report that microinfusions of DA D(1)-like or D(2)-like receptor-specific antagonists into NAcore or NAshell double dissociate the rewarding and aversive properties of systemic or intra-VTA nicotine, and differentially regulate sensitivity to the rewarding properties as well as the motivational valence of either intra-VTA or systemic nicotine administration. Using a place conditioning procedure, NAshell infusions of a D(2)-like receptor antagonist switched the motivational valence of intra-VTA nicotine from aversive to rewarding and potentiated nicotine reward sensitivity to sub-reward threshold intra-VTA nicotine doses. In contrast, NAcore infusions of a D(1)-like receptor antagonist switched intra-VTA nicotine aversion to reward, and potentiated reward sensitivity to sub-reward threshold nicotine doses. Thus, D(1)-like versus D(2)-like receptors in NAcore versus NAshell subdivisions play functionally dissociable roles in modulating systemic or intra-VTA nicotine motivational processing.
Collapse
Affiliation(s)
- Steven R Laviolette
- Department of Anatomy and Cell Biology, The Schulich School of Medicine, University of Western Ontario, London, Ontario, Canada N5Y 5T8.
| | | | | | | | | |
Collapse
|
147
|
Exley R, Clements MA, Hartung H, McIntosh JM, Cragg SJ. Alpha6-containing nicotinic acetylcholine receptors dominate the nicotine control of dopamine neurotransmission in nucleus accumbens. Neuropsychopharmacology 2008; 33:2158-66. [PMID: 18033235 DOI: 10.1038/sj.npp.1301617] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Modulation of striatal dopamine (DA) neurotransmission plays a fundamental role in the reinforcing and ultimately addictive effects of nicotine. Nicotine, by desensitizing beta2 subunit-containing (beta2*) nicotinic acetylcholine receptors (nAChRs) on striatal DA axons, significantly enhances how DA is released by reward-related burst activity compared to nonreward-related tonic activity. This action provides a synaptic mechanism for nicotine to facilitate the DA-dependent reinforcement. The subfamily of beta2*-nAChRs responsible for these potent synaptic effects could offer a molecular target for therapeutic strategies in nicotine addiction. We explored the role of alpha6beta2*-nAChRs in the nucleus accumbens (NAc) and caudate-putamen (CPu) by observing action potential-dependent DA release from synapses in real-time using fast-scan cyclic voltammetry at carbon-fiber microelectrodes in mouse striatal slices. The alpha6-specific antagonist alpha-conotoxin-MII suppressed DA release evoked by single and low-frequency action potentials and concurrently enhanced release by high-frequency bursts in a manner similar to the beta2*-selective antagonist dihydro-beta-erythroidine (DHbetaE) in NAc, but less so in CPu. The greater role for alpha6*-nAChRs in NAc was not due to any confounding regional difference in ACh tone since elevated ACh levels (after the acetylcholinesterase inhibitor ambenonium) had similar outcomes in NAc and CPu. Rather, there appear to be underlying differences in nAChR subtype function in NAc and CPu. In summary, we reveal that alpha6beta2*-nAChRs dominate the effects of nicotine on DA release in NAc, whereas in CPu their role is minor alongside other beta2*-nAChRs (eg alpha4*), These data offer new insights to suggest striatal alpha6*-nAChRs as a molecular target for a therapeutic strategy for nicotine addiction.
Collapse
Affiliation(s)
- Richard Exley
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | | | | | | |
Collapse
|
148
|
Ray R, Loughead J, Wang Z, Detre J, Yang E, Gur R, Lerman C. Neuroimaging, genetics and the treatment of nicotine addiction. Behav Brain Res 2008; 193:159-69. [PMID: 18599130 DOI: 10.1016/j.bbr.2008.05.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 05/29/2008] [Indexed: 12/26/2022]
Abstract
Advances in neuroimaging and genomics provide an unprecedented opportunity to accelerate medication development for nicotine dependence and other addictions. Neuroimaging studies have begun to elucidate the functional neuroanatomy and neurochemistry underlying effects of nicotine and nicotine abstinence. In parallel, genetic studies, including both candidate gene and genome-wide association approaches, are identifying key neurobiological targets and pathways important in addiction to nicotine. To date, only a few neuroimaging studies have explored effects of nicotine or abstinence on brain activity as a function of genotype. Most analyses of genotype are retrospective, resulting in small sample sizes for testing effects of the minor alleles for candidate genes. The purpose of this review is to provide an outline of the work in neuroimaging, genetics, and nicotine dependence, and to explore the potential for increased integration of these approaches to improve nicotine dependence treatment.
Collapse
Affiliation(s)
- Riju Ray
- Trandisciplinary Tobacco Use Research Center, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | |
Collapse
|
149
|
Jain R, Mukherjee K, Balhara YPS. The role of NMDA receptor antagonists in nicotine tolerance, sensitization, and physical dependence: a preclinical review. Yonsei Med J 2008; 49:175-88. [PMID: 18452252 PMCID: PMC2615322 DOI: 10.3349/ymj.2008.49.2.175] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 05/30/2007] [Indexed: 12/04/2022] Open
Abstract
Nicotine, the primary psychoactive component of tobacco products, produces diverse neurophysiological, motivational, and behavioral effects through several brain regions and neurochemical pathways. Various neurotransmitter systems have been explored to understand the mechanisms behind nicotine tolerance, dependence, and withdrawal. Recent evidence suggests that glutamate neurotransmission has an important role in this phenomenon. The aim of the present review is to discuss preclinical findings concerning the role of N-methyl-D-aspartate (NMDA) receptor neurotransmission in mediating the behavioral effects of nicotine, tolerance, sensitization, dependence, and withdrawal. Based on preclinical findings, it is hypothesized that NMDA receptors mediate the common adaptive processes that are involved in the development, maintenance, and expression of nicotine addiction. Modulation of glutamatergic neurotransmission with NMDA receptor antagonists may prove to be useful in alleviating the symptoms of nicotine abstinence and facilitate tobacco-smoking cessation.
Collapse
Affiliation(s)
- Raka Jain
- National Drug Dependence Treatment Centre and Department of Psychiatry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, Pin 110029, India.
| | | | | |
Collapse
|
150
|
Ochoa ELM, Lasalde-Dominicci J. Cognitive deficits in schizophrenia: focus on neuronal nicotinic acetylcholine receptors and smoking. Cell Mol Neurobiol 2008; 27:609-39. [PMID: 17554626 PMCID: PMC4676572 DOI: 10.1007/s10571-007-9149-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Accepted: 04/13/2007] [Indexed: 02/08/2023]
Abstract
Patients with schizophrenia present with deficits in specific areas of cognition. These are quantifiable by neuropsychological testing and can be clinically observable as negative signs. Concomitantly, they self-administer nicotine in the form of cigarette smoking. Nicotine dependence is more prevalent in this patient population when compared to other psychiatric conditions or to non-mentally ill people. The target for nicotine is the neuronal nicotinic acetylcholine receptor (nAChR). There is ample evidence that these receptors are involved in normal cognitive operations within the brain. This review describes neuronal nAChR structure and function, focusing on both cholinergic agonist-induced nAChR desensitization and nAChR up-regulation. The several mechanisms proposed for the nAChR up-regulation are examined in detail. Desensitization and up-regulation of nAChRs may be relevant to the physiopathology of schizophrenia. The participation of several subtypes of neuronal nAChRs in the cognitive processing of non-mentally ill persons and schizophrenic patients is reviewed. The role of smoking is then examined as a possible cognitive remediator in this psychiatric condition. Finally, pharmacological strategies focused on neuronal nAChRs are discussed as possible therapeutic avenues that may ameliorate the cognitive deficits of schizophrenia.
Collapse
Affiliation(s)
- Enrique L. M. Ochoa
- Department of Psychiatry, University of California at Davis, 2230 Stockton Boulevard, Sacramento, CA 95817, USA
| | - Jose Lasalde-Dominicci
- Department of Biology, University of Puerto Rico, Río Piedras Campus, P.O. Box 23360, San Juan 00931-3360, Puerto Rico
| |
Collapse
|