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Han Y, Zhang JQ, Ji YW, Luan YW, Li SY, Geng HZ, Ji Y, Yin C, Liu S, Zhou CY, Xiao C. α4 nicotinic receptors on GABAergic neurons mediate a cholinergic analgesic circuit in the substantia nigra pars reticulata. Acta Pharmacol Sin 2024; 45:1160-1174. [PMID: 38438581 PMCID: PMC11130268 DOI: 10.1038/s41401-024-01234-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/25/2024] [Indexed: 03/06/2024] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) regulate pain pathways with various outcomes depending on receptor subtypes, neuron types, and locations. But it remains unknown whether α4β2 nAChRs abundantly expressed in the substantia nigra pars reticulata (SNr) have potential to mitigate hyperalgesia in pain states. We observed that injection of nAChR antagonists into the SNr reduced pain thresholds in naïve mice, whereas injection of nAChR agonists into the SNr relieved hyperalgesia in mice, subjected to capsaicin injection into the lower hind leg, spinal nerve injury, chronic constriction injury, or chronic nicotine exposure. The analgesic effects of nAChR agonists were mimicked by optogenetic stimulation of cholinergic inputs from the pedunculopontine nucleus (PPN) to the SNr, but attenuated upon downregulation of α4 nAChRs on SNr GABAergic neurons and injection of dihydro-β-erythroidine into the SNr. Chronic nicotine-induced hyperalgesia depended on α4 nAChRs in SNr GABAergic neurons and was associated with the reduction of ACh release in the SNr. Either activation of α4 nAChRs in the SNr or optogenetic stimulation of the PPN-SNr cholinergic projection mitigated chronic nicotine-induced hyperalgesia. Interestingly, mechanical stimulation-induced ACh release was significantly attenuated in mice subjected to either capsaicin injection into the lower hind leg or SNI. These results suggest that α4 nAChRs on GABAergic neurons mediate a cholinergic analgesic circuit in the SNr, and these receptors may be effective therapeutic targets to relieve hyperalgesia in acute and chronic pain, and chronic nicotine exposure.
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Affiliation(s)
- Yu Han
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Department of Anesthesiology, Yiwu Central Hospital, Yiwu, 322099, China
| | - Jia-Qi Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Ya-Wei Ji
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Yi-Wen Luan
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Wuxi People's Hospital, Wuxi, 214023, China
| | - Shu-Yi Li
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Hui-Zhen Geng
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Ying Ji
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Cui Yin
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Su Liu
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
- Department of Anesthesiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221002, China
| | - Chun-Yi Zhou
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China.
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
| | - Cheng Xiao
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China.
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
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Chellian R, Behnood-Rod A, Bruijnzeel AW. Development of Dependence in Smokers and Rodents With Voluntary Nicotine Intake: Similarities and Differences. Nicotine Tob Res 2023; 25:1229-1240. [PMID: 36482774 PMCID: PMC10256892 DOI: 10.1093/ntr/ntac280] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/23/2022] [Accepted: 12/05/2022] [Indexed: 07/29/2023]
Abstract
INTRODUCTION Smoking and vaping throughout adolescence and early adulthood lead to nicotine dependence. Nicotine withdrawal is associated with somatic and affective withdrawal symptoms that contribute to smoking and relapse. Affective nicotine withdrawal symptoms in humans include craving for cigarettes, depression, anxiety, trouble sleeping, and cognitive deficits. METHODS Herein, we review clinical studies that investigated nicotine dependence in people who smoke or vape. We also discuss studies that investigated the development of dependence in animals with oral nicotine intake, nicotine aerosol self-administration, and intravenous nicotine self-administration. RESULTS Clinical studies report that adolescents who smoke daily develop nicotine dependence before those who smoke infrequently, but ultimately all smokers become dependent in adulthood. Preclinical studies indicate that rats that self-administer nicotine also become dependent. Rats that self-administer nicotine display somatic withdrawal signs and affective withdrawal signs, including increased anxiety and depressive-like behavior, cognitive deficits, and allodynia. Most nicotine withdrawal signs were observed in rodents with daily (7 days/week) or intermittent long access (23-hour) to nicotine. Clinical smoking studies report symptoms of nicotine dependence in adolescents of both sexes, but virtually all preclinical nicotine self-administration studies have been done with adult male rats. CONCLUSIONS The role of sex and age in the development of dependence in nicotine self-administration studies remains under-investigated. However, the role of sex and age in nicotine withdrawal has been thoroughly evaluated in studies in which nicotine was administered noncontingently. We discuss the need for volitional nicotine self-administration studies that explore the gradual development of dependence during adolescence and adulthood in rodents of both sexes. IMPLICATIONS The reviewed clinical studies investigated the development of nicotine dependence in male and female adolescent and young adult smokers and vapers. These studies indicate that most adolescent smokers and vapers gradually become nicotine dependent. Preclinical studies with rodents show that nicotine intake in widely used self-administration models also leads to dependence. However, almost all animal studies that investigated the development of nicotine dependence have been conducted with adult male rats. To better model smoking and vaping, it is important that nicotine intake in rats or mice starts during adolescence and that both sexes are included.
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Affiliation(s)
| | - Azin Behnood-Rod
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Adriaan W Bruijnzeel
- Corresponding Author: Adriaan Bruijnzeel, PhD, University of Florida, Department of Psychiatry, 1149 Newell Dr., Gainesville, Florida 32611, USA. Telephone: 352-294-4931; Fax: 352-392-9887; E-mail:
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Lucente E, Söderpalm B, Ericson M, Adermark L. Acute and chronic effects by nicotine on striatal neurotransmission and synaptic plasticity in the female rat brain. Front Mol Neurosci 2023; 15:1104648. [PMID: 36710931 PMCID: PMC9877298 DOI: 10.3389/fnmol.2022.1104648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023] Open
Abstract
Introduction Tobacco use is in part a gendered activity, yet neurobiological studies outlining the effect by nicotine on the female brain are scarce. The aim of this study was to outline acute and sub-chronic effects by nicotine on the female rat brain, with special emphasis on neurotransmission and synaptic plasticity in the dorsolateral striatum (DLS), a key brain region with respect to the formation of habits. Methods In vivo microdialysis and ex vivo electrophysiology were performed in nicotine naïve female Wistar rats, and following sub-chronic nicotine exposure (0.36 mg/kg free base, 15 injections). Locomotor behavior was assessed at the first and last drug-exposure. Results Acute exposure to nicotine ex vivo depresses excitatory neurotransmission by reducing the probability of transmitter release. Bath applied nicotine furthermore facilitated long-term synaptic depression induced by high frequency stimulation (HFS-LTD). The cannabinoid 1 receptor (CB1R) agonist WIN55,212-2 produced a robust synaptic depression of evoked potentials, and HFS-LTD was blocked by the CB1R antagonist AM251, suggesting that HFS-LTD in the female rat DLS is endocannabinoid mediated. Sub-chronic exposure to nicotine in vivo produced behavioral sensitization and electrophysiological recordings performed after 2-8 days abstinence revealed a sustained depression of evoked population spike amplitudes in the DLS, with no concomitant change in paired pulse ratio. Rats receiving sub-chronic nicotine exposure further demonstrated an increased neurophysiological responsiveness to nicotine with respect to both dopaminergic- and glutamatergic signaling. However, a tolerance towards the plasticity facilitating property of bath applied nicotine was developed during sub-chronic nicotine exposure in vivo. In addition, the dopamine D2 receptor agonist quinpirole selectively facilitate HFS-LTD in slices from nicotine naïve rats, suggesting that the tolerance may be associated with changes in dopaminergic signaling. Conclusion Nicotine produces acute and sustained effects on striatal neurotransmission and synaptic plasticity in the female rat brain, which may contribute to the establishment of persistent nicotine taking habits.
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Affiliation(s)
- Erika Lucente
- Integrative Neuroscience Unit, Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Bo Söderpalm
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mia Ericson
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Louise Adermark
- Integrative Neuroscience Unit, Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden,*Correspondence: Louise Adermark, ✉
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Angelyn H, Loney GC, Meyer PJ. Nicotine Enhances Goal-Tracking in Ethanol and Food Pavlovian Conditioned Approach Paradigms. Front Neurosci 2021; 15:561766. [PMID: 34483813 PMCID: PMC8416423 DOI: 10.3389/fnins.2021.561766] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
Rationale Nicotine promotes alcohol intake through pharmacological and behavioral interactions. As an example of the latter, nicotine can facilitate approach toward food- and alcohol-associated stimuli ("sign-tracking") in lever-Pavlovian conditioned approach (PavCA) paradigms. However, we recently reported that nicotine can also enhance approach toward locations of reward delivery ("goal-tracking") triggered by ethanol-predictive stimuli when the location of ethanol delivery is non-static (i.e., a retractable sipper bottle). Objective To determine whether the non-static nature of the reward location could have biased the development of goal-tracking in our previous study (Loney et al., 2019); we assessed the effect of nicotine in a lever-PavCA paradigm wherein the location of ethanol delivery was static (i.e., a stationary liquid receptacle). Then, to determine whether nicotine's enhancement of goal-tracking is unique to ethanol-predictive stimuli, we assessed the effect of systemic nicotine on approach triggered by food-predictive stimuli in a lever-PavCA paradigm. Methods Long-Evans rats were used in two PavCA experiments wherein a lever predicted the receipt of ethanol (15% vol/vol; experiment 1) or food (experiment 2) into a stationary receptacle. Prior to testing, rats were administered nicotine (0.4 mg/kg subcutaneously) or saline systemically. Results In both experiments, nicotine increased measures of goal-tracking, but not sign-tracking. Conclusion Nicotine can facilitate approach to reward locations without facilitating approach to reward-predictive stimuli. As such, conceptualization of the mechanisms by which nicotine affects behavior must be expanded to explain an enhancement of goal-tracking by nicotine.
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Affiliation(s)
- Hailley Angelyn
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States
| | - Gregory C Loney
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States
| | - Paul J Meyer
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States
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Flores RJ, Alshbool FZ, Giner P, O'Dell LE, Mendez IA. Exposure to nicotine vapor produced by an electronic nicotine delivery system causes short-term increases in impulsive choice in adult male rats. Nicotine Tob Res 2021; 24:358-365. [PMID: 34232312 DOI: 10.1093/ntr/ntab141] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 07/05/2021] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Traditional cigarette use influences cost-benefit decision making by promoting impulsive choice. However, the impact of exposure via electronic nicotine delivery systems on impulsive choice remains unclear. Hence, the present study examined the short- and long-term effects of nicotine vapor on impulsive choice. METHODS Twenty-four adult male rats were trained in the delay discounting task, to choose between small, immediate food rewards or large, delayed food rewards. After 24 days of training in the task, rats were exposed to vapor containing either 0, 12, or 24 mg/mL of nicotine, for ten days. To validate inhalation of nicotine vapor, serum cotinine levels were analyzed on exposure days 1, 5, and 10 using enzyme-linked immunosorbent assay (ELISA). Following vapor exposure, rats were retrained in the discounting task until rats displayed stable responding, and the effects of nicotine vapor on choice preference were assessed. RESULTS Rats exposed to 12 and 24 mg/mL nicotine vapor displayed higher serum cotinine levels than control rats exposed to 0 mg/mL vapor. There were no differences in impulsive choice between any vapor exposure groups when tested 15 days after exposure, across 6 days of stable responding, suggesting that nicotine vapor does not have long lasting effects on impulsive choice. Interestingly, a subsequent nicotine vapor challenge revealed short-term increases in impulsive choice immediately following a single exposure to 24 mg/mL nicotine vapor, relative to choice preference immediately following exposure to 0 mg/mL vapor. CONCLUSIONS These results suggest that exposure to nicotine vapor causes immediate, short-term increases in impulsive choice. IMPLICATIONS E-cigarette use is increasing at an alarming rate, particularly among adolescents and young adults. This is concerning given the lack of research into the effects of nicotine vapor exposure on the brain and behavior. The present study describes a viable rodent model of human e-cigarette use and suggest that exposure to nicotine vapor produces short-term increases in impulsive choice.
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Affiliation(s)
- Rodolfo J Flores
- The University of Texas at El Paso, Department of Psychology, El Paso, Texas, USA
| | - Fatima Z Alshbool
- Texas A&M University, Irma Lerma Rangel College of Pharmacy, Department of Pharmacy Practice, Kingsville, Texas, USA
| | - Priscilla Giner
- The University of Texas at El Paso, School of Pharmacy, Department of Pharmaceutical Sciences, El Paso, Texas, USA
| | - Laura E O'Dell
- The University of Texas at El Paso, Department of Psychology, El Paso, Texas, USA
| | - Ian A Mendez
- The University of Texas at El Paso, School of Pharmacy, Department of Pharmaceutical Sciences, El Paso, Texas, USA
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Varani AP, Pedrón VT, Aon AJ, Canero EM, Balerio GN. GABA B receptors blockage modulates somatic and aversive manifestations induced by nicotine withdrawal. Biomed Pharmacother 2021; 140:111786. [PMID: 34144406 DOI: 10.1016/j.biopha.2021.111786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 10/21/2022] Open
Abstract
There is substantial evidence that GABAB agonist, baclofen, prevents somatic and motivational responses induced by nicotine withdrawal and may target drug cue vulnerabilities in humans. In this context, we explored different aspects associated with the possible mechanisms whereby the GABAB receptors might influence nicotine withdrawal. Male mice received nicotine (2.5 mg/kg, s.c.) 4 times daily, for 7 consecutive days. Nicotine-treated mice received the nicotinic acetylcholine receptor antagonist, mecamylamine (MEC, 2 or 3.5 mg/kg, s.c.), to precipitate the withdrawal state. A second group of dependent mice received 2-hydroxysaclofen (GABAB receptor antagonist, 1 mg/kg, s.c.) before MEC-precipitated abstinence. Somatic signs of nicotine withdrawal were measured for 30 min. Anxiogenic-like response associated to nicotine withdrawal was assessed by the elevated plus maze test. The dysphoric/aversive effect induced by nicotine withdrawal was evaluated using conditioned place aversion paradigm. Dopamine, serotonin and its metabolites concentrations were determined by HPLC in the striatum, cortex and hippocampus. Finally, α4β2 nicotinic acetylcholine receptor density was determined in several brain regions using autoradiography assays. The results showed that MEC-precipitated nicotine withdrawal induced somatic manifestations, anxiogenic-like response and dysphoric/aversive effect, and 2-hydroxysaclofen potentiated these behavioral responses. Additionally, 2-hydroxysaclofen was able to change striatal dopamine levels and α4β2 nicotinic acetylcholine receptor density, both altered by MEC-precipitated nicotine withdrawal. These findings provide important contributions to elucidate neurobiological mechanisms implicated in nicotine withdrawal. We suggest that GABAB receptor activity is necessary to control alterations induced by nicotine withdrawal, which supports the idea of targeting GABAB receptors to treat tobacco addiction in humans.
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Affiliation(s)
- A P Varani
- CONICET, Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina
| | - V T Pedrón
- CONICET, Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina
| | - A J Aon
- CONICET, Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina
| | - E M Canero
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica (FFYB), Cátedra de Farmacología, Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina; CONICET, Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina
| | - G N Balerio
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica (FFYB), Cátedra de Farmacología, Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina; CONICET, Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Junín 956, 5° Piso, Buenos Aires C1113AAD, Argentina.
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Jin XT, Tucker BR, Drenan RM. Nicotine Self-Administration Induces Plastic Changes to Nicotinic Receptors in Medial Habenula. eNeuro 2020; 7:ENEURO.0197-20.2020. [PMID: 32675176 PMCID: PMC7405075 DOI: 10.1523/eneuro.0197-20.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/03/2020] [Accepted: 06/09/2020] [Indexed: 11/21/2022] Open
Abstract
Chronic nicotine upregulates nicotinic acetylcholine receptors (nAChRs) throughout the brain, and reducing their activity may promote somatic and affective states that lead to nicotine seeking. nAChRs are functionally upregulated in animal models using passive nicotine administration, but whether/how it occurs in response to volitional nicotine intake is unknown. The distinction is critical, as drug self-administration (SA) can induce neurotransmission and cellular excitability changes that passive drug administration does not. In this study, we probed the question of whether medial habenula (MHb) nAChRs are functionally augmented by nicotine SA. Male rats were implanted with an indwelling jugular catheter and trained to nose poke for nicotine infusions. A saline SA group controlled for non-specific responding and nicotine-associated visual cues. Using patch-clamp whole-cell recordings and local application of acetylcholine, we observed robust functional enhancement of nAChRs in MHb neurons from rats with a history of nicotine SA. To determine whether upregulated receptors are generally enhanced or directed to specific cellular compartments, we imaged neurons during recordings using two-photon laser scanning microscopy (2PLSM). nAChR activity at the cell soma and on proximal and distal dendrites was examined by local nicotine uncaging using a photoactivatable nicotine (PA-Nic) probe and focal laser flash photolysis. Results from this experiment revealed strong nAChR enhancement at all examined cellular locations. Our study demonstrates nAChR functional enhancement by nicotine SA, confirming that volitional nicotine intake sensitizes cholinergic systems in the brain. This may be a critical plasticity change supporting nicotine addiction.
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Affiliation(s)
- Xiao-Tao Jin
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Brenton R Tucker
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Ryan M Drenan
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
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Neural circuits and nicotinic acetylcholine receptors mediate the cholinergic regulation of midbrain dopaminergic neurons and nicotine dependence. Acta Pharmacol Sin 2020; 41:1-9. [PMID: 31554960 PMCID: PMC7468330 DOI: 10.1038/s41401-019-0299-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/06/2019] [Indexed: 12/23/2022] Open
Abstract
Midbrain dopaminergic (DA) neurons are governed by an endogenous cholinergic system, originated in the mesopontine nuclei. Nicotine hijacks nicotinic acetylcholine receptors (nAChRs) and interferes with physiological function of the cholinergic system. In this review, we describe the anatomical organization of the cholinergic system and the key nAChR subtypes mediating cholinergic regulation of DA transmission and nicotine reward and dependence, in an effort to identify potential targets for smoking intervention. Cholinergic modulation of midbrain DA systems relies on topographic organization of mesopontine cholinergic projections, and activation of nAChRs in midbrain DA neurons. Previous studies have revealed that α4, α6, and β2 subunit-containing nAChRs expressed in midbrain DA neurons and their terminals in the striatum regulate firings of midbrain DA neurons and activity-dependent dopamine release in the striatum. These nAChRs undergo modification upon chronic nicotine exposure. Clinical investigation has demonstrated that partial agonists of these receptors elevate the success rate of smoking cessation relative to placebo. However, further investigations are required to refine the drug targets to mitigate unpleasant side-effects.
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Perry RN, Schlagintweit HE, Darredeau C, Helmick C, Newman AJ, Good KP, Barrett SP. The impacts of actual and perceived nicotine administration on insula functional connectivity with the anterior cingulate cortex and nucleus accumbens. J Psychopharmacol 2019; 33:1600-1609. [PMID: 31542980 PMCID: PMC6854612 DOI: 10.1177/0269881119872205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Changes in resting state functional connectivity between the insula and dorsal anterior cingulate cortex as well as between the insula and nucleus accumbens have been linked to nicotine withdrawal and/or administration. However, because many of nicotine's effects in humans appear to depend, at least in part, on the belief that nicotine has been administered, the relative contribution of nicotine's pharmacological actions to such effects requires clarification. AIMS The purpose of this study was to examine the impacts of perceived and actual nicotine administration on neural responses. METHODS Twenty-six smokers were randomly assigned to receive either a nicotine inhaler (4 mg deliverable) or a nicotine-free inhaler across two sessions. Inhaler content instructions (told nicotine vs told nicotine-free) differed across sessions. Resting state functional connectivity between sub-regions of the insula and the dorsal anterior cingulate cortex and nucleus accumbens was measured using magnetic resonance imaging before and after inhaler administration. RESULTS Both actual and perceived nicotine administration independently altered resting state functional connectivity between the anterior insula and the dorsal anterior cingulate cortex, with actual administration being associated with decreased resting state functional connectivity, and perceived administration with increased resting state functional connectivity. Actual nicotine administration also contralaterally reduced resting state functional connectivity between the anterior insula and nucleus accumbens, while reductions in resting state functional connectivity between the mid-insula and right nucleus accumbens were observed when nicotine was administered unexpectedly. Changes in resting state functional connectivity associated with actual or perceived nicotine administration were unrelated to changes in subjective withdrawal and craving. Changes in withdrawal and craving were however independently associated with resting state functional connectivity between the nucleus accumbens and insula. CONCLUSIONS Our findings highlight the importance of considering non-pharmacological factors when examining drug mechanisms of action.
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Affiliation(s)
- Robin N Perry
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Hera E Schlagintweit
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Christine Darredeau
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Carl Helmick
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
| | - Aaron J Newman
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada,Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
| | - Kimberley P Good
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada,Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
| | - Sean P Barrett
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada,Department of Psychiatry, Dalhousie University, Halifax, NS, Canada,Sean P. Barrett, Department of Psychology and Neuroscience, Dalhousie University, Life Sciences Centre, P.O. Box 15000, Halifax, NS, B3H 4R2, Canada.
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Trigo JM, Le Foll B. Nicotine Self-Administration as Paradigm for Medication Discovery for Smoking Cessation: Recent Findings in Medications Targeting the Cholinergic System. Methods Mol Biol 2019; 2011:165-193. [PMID: 31273700 DOI: 10.1007/978-1-4939-9554-7_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tobacco kills every year approximately six million people as a direct result of direct use, and it is still considered one of the most excruciating threats for human health worldwide. The low successful rates of the currently available pharmacotherapies to assist in quitting tobacco use suggest there is a need for more effective treatments.The intravenous self-administration (IVSA) paradigm is considered the gold standard to study voluntary drug intake in animal models, including nicotine. The IVSA paradigm has been used to identify key mechanisms involved in the addictive properties of nicotine in both rodents and nonhuman primates. In this chapter we describe how the IVSA paradigm has served to further investigate the role of nicotinic acetylcholine receptors (nAChRs) in the reinforcing properties of nicotine. Notably, this review will cover recent advances (i.e., research carried out during the past decade) using the IVSA paradigm, with a focus on the status of research on current smoking cessation medications (such as varenicline and bupropion) and of other nAChR ligands.The combination of the IVSA paradigm with pharmacological and genetic tools (e.g., knockout animals) has greatly contributed to our understanding of the role of specific subtype nAChRs in nicotine reinforcement processes. We also discuss some of the limitations of the IVSA paradigm so these can be taken into consideration when interpreting and designing new studies.
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Affiliation(s)
- Jose M Trigo
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Bernard Le Foll
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.
- Addictions Division, CAMH, Toronto, ON, Canada.
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Vassoler FM, Oranges ML, Toorie AM, Byrnes EM. Oxycodone self-administration during pregnancy disrupts the maternal-infant dyad and decreases midbrain OPRM1 expression during early postnatal development in rats. Pharmacol Biochem Behav 2018; 173:74-83. [PMID: 30055180 DOI: 10.1016/j.pbb.2018.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 12/30/2022]
Abstract
Opioid use and abuse has reached epidemic levels in the United States. As these drugs are frequently used by women of reproductive age, there has been a significant increase in the number of infants born to opioid dependent women. Few preclinical studies have examined voluntary opioid intake during pregnancy, and none have used intravenous self-administration. Thus, the purpose of the current set of studies was to utilize a translational model of oxycodone self-administration in rats to determine the effects of oxycodone intake during pregnancy on early postnatal outcomes. Females were trained to intravenously self-administer oxycodone several weeks prior to mating and then continuously throughout pregnancy followed by withdrawal around the time of parturition. Offspring were monitored for weight gain and separation-induced ultrasonic vocalizations (i.e. number of calls) while dams were examined for motivated maternal responding. Neural expression of the mu opioid receptor gene OPRM1 was examined in offspring on postnatal day 1 (PND1). Results indicate that females self-administer oxycodone during pregnancy at levels similar to those observed in cycling females. Postpartum, oxycodone withdrawn females demonstrate impaired maternal responding. In offspring, while no significant group effects were observed on body weight or call number, age-dependent alterations in weight gain and call number correlated with the dams cumulative oxycodone dose during pregnancy. In addition, offspring demonstrated region specific effects of oxycodone exposure on OPRM1 on PND1. Overall, these findings demonstrate that pregnant females will voluntarily self-administer oxycodone at levels similar to cycling females when using a short access model. Further, maternal oxycodone self-administration alters the maternal-offspring dyad in a manner that is dose-dependent and results in sex- and region-specific effects on OPRM1 expression.
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Affiliation(s)
- Fair M Vassoler
- Cummings School of Veterinary Medicine, Tuft University, North Grafton, MA 02536, United States of America
| | - Michelle L Oranges
- Cummings School of Veterinary Medicine, Tuft University, North Grafton, MA 02536, United States of America
| | - Anika M Toorie
- Cummings School of Veterinary Medicine, Tuft University, North Grafton, MA 02536, United States of America
| | - Elizabeth M Byrnes
- Cummings School of Veterinary Medicine, Tuft University, North Grafton, MA 02536, United States of America.
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Semenova S, Jin X, McClure-Begley TD, Tadman MP, Marks MJ, Markou A. Differential effects of withdrawal from intermittent and continuous nicotine exposure on reward deficit and somatic aspects of nicotine withdrawal and expression of α4β2* nAChRs in Wistar male rats. Pharmacol Biochem Behav 2018; 171:54-65. [PMID: 29908200 DOI: 10.1016/j.pbb.2018.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/03/2018] [Accepted: 06/12/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Chronic nicotine exposure produces neuroadaptations in brain reward systems and α4β2 nicotinic acetylcholine receptors (nAChRs) in the corticolimbic brain areas. We previously demonstrated opposite effects of nicotine exposure delivered by self-administration or pumps on brain reward thresholds that can be attributed to the different temporal pattern and contingency of nicotine exposure. We investigated the effects of these two factors on reward thresholds and somatic signs during nicotine withdrawal, and on nAChRs binding in corticolimbic brain areas. METHODS The intracranial self-stimulation procedure was used to assess reward thresholds in rats prepared with pumps delivering various doses of nicotine continuously or intermittently. Separate group of rats were randomly exposed to nicotine via pumps (non-contingent) or nicotine self-administration (contingent) to determine [125I]-epibatidine binding at α4β2* nAChRs. RESULTS Withdrawal from continuous non-contingent nicotine exposure led to significant elevations in thresholds and increases in somatic signs in rats, while there was no significant effect of withdrawal from intermittent non-contingent nicotine exposure at the same doses. nAChRs were upregulated during withdrawal from continuous non-contingent nicotine exposure. α4β2* nAChRs were upregulated in the ventral tegmental area and prelimbic cortex during withdrawal from non-contingent intermittent exposure and in the nucleus accumbens during withdrawal from contingent intermittent nicotine exposure to the same dose. CONCLUSIONS During non-contingent nicotine exposure, the temporal pattern of nicotine delivery differentially affected thresholds and somatic signs of withdrawal. Upregulation of α4β2* nAChRs was brain site-specific and depended on both temporal pattern and contingency of nicotine exposure.
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Affiliation(s)
- Svetlana Semenova
- Department of Psychiatry, School of Medicine, University California San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA.
| | - Xinchun Jin
- Department of Psychiatry, School of Medicine, University California San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
| | | | | | - Michael J Marks
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA; Department of Psychology and Neuroscience, University of Colorado, Boulder, CO 80309, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University California San Diego, 9500 Gilman Drive, M/C 0603, La Jolla, CA 92093, USA
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Wright SR, Zanos P, Georgiou P, Yoo JH, Ledent C, Hourani SM, Kitchen I, Winsky-Sommerer R, Bailey A. A critical role of striatal A2A R-mGlu5 R interactions in modulating the psychomotor and drug-seeking effects of methamphetamine. Addict Biol 2016; 21:811-25. [PMID: 25975203 DOI: 10.1111/adb.12259] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Addiction to psychostimulants is a major public health problem with no available treatment. Adenosine A2A receptors (A2A R) co-localize with metabotropic glutamate 5 receptors (mGlu5 R) in the striatum and functionally interact to modulate behaviours induced by addictive substances, such as alcohol. Using genetic and pharmacological antagonism of A2A R in mice, we investigated whether A2A R-mGlu5 R interaction can regulate the locomotor, stereotypic and drug-seeking effect of methamphetamine and cocaine, two drugs that exhibit distinct mechanism of action. Genetic deletion of A2A R, as well as combined administration of sub-threshold doses of the selective A2A R antagonist (SCH 58261, 0.01 mg/kg, i.p.) with the mGlu5 R antagonist, 3-((2-methyl-4-thiazolyl)ethynyl)pyridine (0.01 mg/kg, i.p.), prevented methamphetamine- but not cocaine-induced hyperactivity and stereotypic rearing behaviour. This drug combination also prevented methamphetamine-rewarding effects in a conditioned-place preference paradigm. Moreover, mGlu5 R binding was reduced in the nucleus accumbens core of A2A R knockout (KO) mice supporting an interaction between these receptors in a brain region crucial in mediating addiction processes. Chronic methamphetamine, but not cocaine administration, resulted in a significant increase in striatal mGlu5 R binding in wild-type mice, which was absent in the A2A R KO mice. These data are in support of a critical role of striatal A2A R-mGlu5 R functional interaction in mediating the ambulatory, stereotypic and reinforcing effects of methamphetamine but not cocaine-induced hyperlocomotion or stereotypy. The present study highlights a distinct and selective mechanistic role for this receptor interaction in regulating methamphetamine-induced behaviours and suggests that combined antagonism of A2A R and mGlu5 R may represent a novel therapy for methamphetamine addiction.
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Affiliation(s)
- Sherie R. Wright
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Panos Zanos
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Polymnia Georgiou
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Ji-Hoon Yoo
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Catherine Ledent
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire; Université Libre de Bruxelles; Belgium
| | - Susanna M. Hourani
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Ian Kitchen
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Raphaelle Winsky-Sommerer
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Alexis Bailey
- Sleep, Chronobiology and Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
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14
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O'Rourke KY, Touchette JC, Hartell EC, Bade EJ, Lee AM. Voluntary co-consumption of alcohol and nicotine: Effects of abstinence, intermittency, and withdrawal in mice. Neuropharmacology 2016; 109:236-246. [PMID: 27342124 DOI: 10.1016/j.neuropharm.2016.06.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 06/16/2016] [Accepted: 06/21/2016] [Indexed: 11/17/2022]
Abstract
Alcohol and nicotine are often used together, and there is a high rate of co-occurrence between alcohol and nicotine addiction. Most animal models studying alcohol and nicotine interactions have utilized passive drug administration, which may not be relevant to human co-addiction. In addition, the interactions between alcohol and nicotine in female animals have been understudied, as most studies have used male animals. To address these issues, we developed models of alcohol and nicotine co-consumption in male and female mice that utilized voluntary, oral consumption of unsweetened alcohol, nicotine and water. We first examined drug consumption and preference in single-drug, sequential alcohol and nicotine consumption tests in male and female C57BL/6 and DBA/2J mice. We then tested chronic continuous and intermittent access alcohol and nicotine co-consumption procedures. We found that male and female C57BL/6 mice readily co-consumed unsweetened alcohol and nicotine. In our continuous co-consumption procedures, we found that varying the available nicotine concentration during an alcohol abstinence period affected compensatory nicotine consumption during alcohol abstinence, and affected rebound alcohol consumption when alcohol was re-introduced. Consumption of alcohol and nicotine in an intermittent co-consumption procedure produced higher alcohol consumption levels, but not nicotine consumption levels, compared with the continuous co-consumption procedures. Finally, we found that intermittent alcohol and nicotine co-consumption resulted in physical dependence. Our data show that these voluntary co-consumption procedures can be easily performed in mice and can be used to study behavioral interactions between alcohol and nicotine consumption, which may better model human alcohol and nicotine co-addiction.
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Affiliation(s)
- Kyu Y O'Rourke
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | | | - Elizabeth C Hartell
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Elizabeth J Bade
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Anna M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.
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15
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Georgiou P, Zanos P, Ehteramyan M, Hourani S, Kitchen I, Maldonado R, Bailey A. Differential regulation of mGlu5 R and ΜOPr by priming- and cue-induced reinstatement of cocaine-seeking behaviour in mice. Addict Biol 2015; 20:902-12. [PMID: 25522112 DOI: 10.1111/adb.12208] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The key problem for the treatment of drug addiction is relapse to drug use after abstinence that can be triggered by drug-associated cues, re-exposure to the drug itself and stress. Understanding the neurobiological mechanisms underlying relapse is essential in order to develop effective pharmacotherapies for its prevention. Given the evidence implicating the metabotropic glutamate receptor 5 (mGlu5 R), μ-opioid receptor (MOPr), κ-opioid receptor (ΚOPr) and oxytocin receptor (OTR) systems in cocaine addiction and relapse, our aim was to assess the modulation of these receptors using a mouse model of cue- and priming-induced reinstatement of cocaine seeking. Male mice were trained to self-administer cocaine (1 mg/kg/infusion, i.v.) and were randomized into different groups: (1) cocaine self-administration; (2) cocaine extinction; (3) cocaine-primed (10 mg/kg i.p.); or (4) cue-induced reinstatement of cocaine seeking. Mice undergoing the same protocols but receiving saline instead of cocaine were used as controls. Quantitative autoradiography of mGlu5 R, MOPr, KOPr and OTR showed a persistent cocaine-induced upregulation of the mGlu5 R and OTR in the lateral septum and central amygdala, respectively. Moreover, a downregulation of mGlu5 R and MOPr was observed in the basolateral amygdala and striatum, respectively. Further, we showed that priming- but not cue-induced reinstatement upregulates mGlu5 R and MOPr binding in the nucleus accumbens core and basolateral amygdala, respectively, while cue- but not priming-induced reinstatement downregulates MOPr binding in caudate putamen and nucleus accumbens core. This is the first study to provide direct evidence of reinstatement-induced receptor alterations that are likely to contribute to the neurobiological mechanisms underpinning relapse to cocaine seeking.
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Affiliation(s)
- Polymnia Georgiou
- Sleep, Chronobiology & Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Panos Zanos
- Sleep, Chronobiology & Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Mazdak Ehteramyan
- Department of Experimental and Health Sciences; University of Pompeu Fabra; Spain
| | - Susanna Hourani
- Sleep, Chronobiology & Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Ian Kitchen
- Sleep, Chronobiology & Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
| | - Rafael Maldonado
- Department of Experimental and Health Sciences; University of Pompeu Fabra; Spain
| | - Alexis Bailey
- Sleep, Chronobiology & Addiction Group; School of Biosciences and Medicine; Faculty of Health and Medical Sciences; University of Surrey; UK
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16
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Hadad NA, Knackstedt LA. Addicted to palatable foods: comparing the neurobiology of Bulimia Nervosa to that of drug addiction. Psychopharmacology (Berl) 2014; 231:1897-912. [PMID: 24500676 PMCID: PMC4484591 DOI: 10.1007/s00213-014-3461-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 01/20/2014] [Indexed: 12/18/2022]
Abstract
RATIONALE Bulimia nervosa (BN) is highly comorbid with substance abuse and shares common phenotypic and genetic predispositions with drug addiction. Although treatments for the two disorders are similar, controversy remains about whether BN should be classified as addiction. OBJECTIVES Here, we review the animal and human literature with the goal of assessing whether BN and drug addiction share a common neurobiology. RESULTS Similar neurobiological features are present following administration of drugs and bingeing on palatable food, especially sugar. Specifically, both disorders involve increases in extracellular dopamine (DA), D1 binding, D3 messenger RNA (mRNA), and ΔFosB in the nucleus accumbens (NAc). Animal models of BN reveal increases in ventral tegmental area (VTA) DA and enzymes involved in DA synthesis that resemble changes observed after exposure to addictive drugs. Additionally, alterations in the expression of glutamate receptors and prefrontal cortex activity present in human BN or following sugar bingeing in animals are comparable to the effects of addictive drugs. The two disorders differ in regards to alterations in NAc D2 binding, VTA DAT mRNA expression, and the efficacy of drugs targeting glutamate to treat these disorders. CONCLUSIONS Although additional empirical studies are necessary, the synthesis of the two bodies of research presented here suggests that BN shares many neurobiological features with drug addiction. While few Food and Drug Administration-approved options currently exist for the treatment of drug addiction, pharmacotherapies developed in the future, which target the glutamate, DA, and opioid systems, may be beneficial for the treatment of both BN and drug addiction.
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Affiliation(s)
- Natalie A Hadad
- Department of Psychology, University of Florida, P.O. Box 112250, Gainesville, FL, 32611-2250, USA
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Hambsch B, Keyworth H, Lind J, Otte DM, Racz I, Kitchen I, Bailey A, Zimmer A. Chronic nicotine improves short-term memory selectively in a G72 mouse model of schizophrenia. Br J Pharmacol 2014; 171:1758-71. [PMID: 24417347 PMCID: PMC3966754 DOI: 10.1111/bph.12578] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 04/18/2013] [Accepted: 12/29/2013] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND AND PURPOSE The prevalence of smoking in schizophrenia patients is exceptionally high; it is not known why but many researchers suggest that smoking constitutes a form of self-medication. Among the symptoms of schizophrenia that may be improved by nicotine are cognitive deficits. Hence, we studied the effects of long-term nicotine administration on cognition in a genetic animal model of schizophrenia susceptibility, G72-transgenic (G72Tg) mice. EXPERIMENTAL APPROACH The effect of long-term nicotine or saline, administered by osmotic minipumps, on different cognitive domains was assessed in G72Tg mice and controls using a battery of behavioural tests. To investigate the mechanism underlying phenotypic differences, quantitative autoradiographic mapping of nACh receptor subtypes was performed in forebrain structures to explore effects of chronic nicotine exposure on nACh receptor density in wild-type (WT) and G72Tg mice. KEY RESULTS Genotype significantly affected the cognitive effects of chronic nicotine administration. Whereas chronic nicotine disrupted cognitive performance in WT mice, it was effective at restoring impaired prepulse inhibition, working memory and social recognition in G72Tg mice. However, long-term spatial learning was further impaired by nicotine in transgenic animals. In contrast, associative learning was protected by G72-expression against the adverse nicotine effects seen in WT animals. G72-expression did not decisively influence nicotine-induced up-regulation of the α4β2*subtype, whereas α7nACh receptor density was differentially altered by genotype or by a genotype·treatment interaction in specific brain areas, most notably hippocampal subregions. CONCLUSIONS AND IMPLICATIONS Our data support the hypothesis that nicotine self-medication of schizophrenics improves cognitive symptoms, possibly by facilitating nicotine-induced α7nACh receptor activation in the hippocampus.
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Affiliation(s)
- B Hambsch
- Institute of Molecular Psychiatry, University of BonnBonn, Germany
| | - H Keyworth
- Department of Biochemistry and Physiology, University of SurreySurrey, UK
| | - J Lind
- Department of Biochemistry and Physiology, University of SurreySurrey, UK
| | - D M Otte
- Institute of Molecular Psychiatry, University of BonnBonn, Germany
| | - I Racz
- Institute of Molecular Psychiatry, University of BonnBonn, Germany
| | - I Kitchen
- Department of Biochemistry and Physiology, University of SurreySurrey, UK
| | - A Bailey
- Department of Biochemistry and Physiology, University of SurreySurrey, UK
| | - A Zimmer
- Institute of Molecular Psychiatry, University of BonnBonn, Germany
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Flores Á, Maldonado R, Berrendero F. The hypocretin/orexin receptor-1 as a novel target to modulate cannabinoid reward. Biol Psychiatry 2014; 75:499-507. [PMID: 23896204 DOI: 10.1016/j.biopsych.2013.06.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/22/2013] [Accepted: 06/19/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND Cannabis is the most widely used illicit drug in the world. Although there is a high prevalence of users who seek treatment for cannabis dependence, no accepted pharmacologic treatment is available to facilitate and maintain abstinence. The hypocretin/orexin system plays a critical role in drug addiction, but the potential participation of this system in the addictive properties of cannabinoids is unknown. METHODS We investigated the effects of hypocretins in the intravenous self-administration of the synthetic cannabinoid agonist WIN55,212-2 using hypocretin receptor-1 (Hcrtr-1) and hypocretin receptor-2 antagonists and Hcrtr-1 knockout mice. Additional groups of mice were trained to obtain water to rule out operant responding impairments. Activation of hypocretin neurons was analyzed by using double-label immunofluorescence of FosB/ΔFosB with hypocretin-1. Microdialysis studies were performed to evaluate dopamine extracellular levels in the nucleus accumbens after acute Δ(9)-tetrahydrocannabinol administration. RESULTS Systemic administration of the Hcrtr-1 antagonist SB334867 reduced intravenous self-administration of WIN55,212-2, as well as the maximum effort to obtain a WIN55,212-2 infusion, as revealed under a progressive ratio schedule. This role of Hcrtr-1 in the reinforcing and motivational properties of WIN55,212-2 was confirmed in Hcrtr-1 knockout mice. Contingent, but not noncontingent, WIN55,212-2 self-administration increased the percentage of hypocretin cells expressing FosB/ΔFosB in the lateral hypothalamus. The enhancement in dopamine extracellular levels in the nucleus accumbens induced by Δ(9)-tetrahydrocannabinol was blocked in mice lacking the Hcrtr-1. CONCLUSIONS These findings demonstrate that Hcrtr-1 modulates the reinforcing properties of cannabinoids, which could have a clear therapeutic interest.
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Affiliation(s)
- África Flores
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Fernando Berrendero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
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The ClockΔ19 mutation in mice fails to alter the primary and secondary reinforcing properties of nicotine. Drug Alcohol Depend 2013; 133:733-9. [PMID: 24054990 DOI: 10.1016/j.drugalcdep.2013.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/27/2013] [Accepted: 08/27/2013] [Indexed: 01/26/2023]
Abstract
BACKGROUND Clock genes have been demonstrated to play a role in behavioral responses to a variety of drugs of abuse, including cocaine, amphetamine, morphine, and ethanol. However, no studies to date have examined the role of Clock genes on nicotine-mediated behaviors. We examined the involvement of Clock, one of several Clock genes, on the effects of nicotine by examining mice with the ClockΔ19 mutation in behaviors commonly used to assess drug effects in rodents. METHODS We first measured the locomotor effects of nicotine in mutants and wild type mice in response to repeated nicotine injections (0.175 mg/kg, IP). To assess the secondary properties of nicotine, we measured the ability of nicotine (0.175 mg/kg, IP) to induce a conditioned place preference. Finally, we measured the primary reinforcing properties of nicotine at two doses (0.01 and 0.03 mg/kg/infusion, IV) using the self-administration paradigm. RESULTS Mutant mice demonstrated no difference in magnitude of the sensitized response to nicotine as compared to wild-type controls. In the conditioned place preference paradigm, mutant and wild-type mice demonstrated a similar preference for a nicotine-paired environment. And finally, mutant and wild-type mice demonstrated a similar acquisition of nicotine self-administration, as indicated by the number of responses on a nicotine-paired lever and the number of nicotine reinforcers achieved during sessions. CONCLUSIONS The ClockΔ19 mutation appears to have no effect on the reinforcing properties of nicotine, in contrast to its demonstrated role in cocaine reinforcement. Further studies are needed to determine the effect of other Clock genes on nicotine reinforcement.
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Hansen HH, Jensen MM, Overgaard A, Weikop P, Mikkelsen JD. Tesofensine induces appetite suppression and weight loss with reversal of low forebrain dopamine levels in the diet-induced obese rat. Pharmacol Biochem Behav 2013; 110:265-71. [DOI: 10.1016/j.pbb.2013.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/15/2013] [Accepted: 07/26/2013] [Indexed: 12/15/2022]
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Varani AP, Antonelli MC, Balerio GN. Mecamylamine-precipitated nicotine withdrawal syndrome and its prevention with baclofen: an autoradiographic study of α4β2 nicotinic acetylcholine receptors in mice. Prog Neuropsychopharmacol Biol Psychiatry 2013; 44:217-25. [PMID: 23500668 DOI: 10.1016/j.pnpbp.2013.02.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 02/13/2013] [Accepted: 02/27/2013] [Indexed: 11/26/2022]
Abstract
A previous study from our laboratory showed that baclofen (BAC, GABAB receptor agonist) was able to prevent the behavioral expression of nicotine (NIC) withdrawal syndrome. To further investigate the mechanisms underlying this effect, we conducted this study, with the aims of analyzing α4β2 nicotinic receptor density during NIC withdrawal and, in case we found any changes, of determining whether they could be prevented by pretreatment with BAC. Swiss Webster albino mice received NIC (2.5 mg/kg, s.c.) 4 times daily, for 7 days. On the 8th day, NIC-treated mice received the nicotinic antagonist mecamylamine (MEC; 2 mg/kg, i.p.) 1 h after the last dose of NIC. A second group of NIC-treated mice received BAC (2 mg/kg, i.p.) prior to MEC administration. Thirty minutes after MEC, mice were sacrificed and brain autoradiography with [(3)H]epibatidine was carried out at five different anatomical levels. Autoradiographic mapping showed a significant increase of α4β2 nicotinic receptor labeling during NIC withdrawal in the nucleus accumbens shell (AcbSh), medial habenular nucleus (HbM), thalamic nuclei, dorsal lateral geniculate (DLG) nucleus, fasciculus retroflexus (fr), ventral tegmental area, interpeduncular nucleus and superior colliculus. BAC pretreatment prevented the increased α4β2 nicotinic receptor binding sites in the AcbSh, MHb, thalamic nuclei, DLG nucleus and fr. The present results suggest a relationship between BAC's preventive effect of the expression of NIC withdrawal signs, and its ability to restore the changes in α4β2 nicotinic receptor labeling, evidenced in specific brain areas in NIC withdrawn animals.
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Affiliation(s)
- Andrés P Varani
- Instituto de Investigaciones Farmacológicas (UBA-CONICET), Junín 956, 5° Piso, C1113AAD, Buenos Aires, Argentina
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Parker CC, Chen H, Flagel SB, Geurts AM, Richards JB, Robinson TE, Solberg Woods LC, Palmer AA. Rats are the smart choice: Rationale for a renewed focus on rats in behavioral genetics. Neuropharmacology 2013; 76 Pt B:250-8. [PMID: 23791960 DOI: 10.1016/j.neuropharm.2013.05.047] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/15/2013] [Accepted: 05/17/2013] [Indexed: 12/13/2022]
Abstract
Due in part to their rich behavioral repertoire rats have been widely used in behavioral studies of drug abuse-related traits for decades. However, the mouse became the model of choice for researchers exploring the genetic underpinnings of addiction after the first mouse study was published demonstrating the capability of engineering the mouse genome through embryonic stem cell technology. The sequencing of the mouse genome and more recent re-sequencing of numerous inbred mouse strains have further cemented the status of mice as the premier mammalian organism for genetic studies. As a result, many of the behavioral paradigms initially developed and optimized for rats have been adapted to mice. However, numerous complex and interesting drug abuse-related behaviors that can be studied in rats are very difficult or impossible to adapt for use in mice, impeding the genetic dissection of those traits. Now, technological advances have removed many of the historical limitations of genetic studies in rats. For instance, the rat genome has been sequenced and many inbred rat strains are now being re-sequenced and outbred rat stocks are being used to fine-map QTLs. In addition, it is now possible to create "knockout" rats using zinc finger nucleases (ZFN), transcription activator-like effector nucleases (TALENs) and related techniques. Thus, rats can now be used to perform quantitative genetic studies of sophisticated behaviors that have been difficult or impossible to study in mice. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Clarissa C Parker
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
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23
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Metaxas A, Al-Hasani R, Farshim P, Tubby K, Berwick A, Ledent C, Hourani S, Kitchen I, Bailey A. Genetic deletion of the adenosine A(2A) receptor prevents nicotine-induced upregulation of α7, but not α4β2* nicotinic acetylcholine receptor binding in the brain. Neuropharmacology 2013; 71:228-36. [PMID: 23583933 DOI: 10.1016/j.neuropharm.2013.03.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 03/11/2013] [Accepted: 03/22/2013] [Indexed: 10/27/2022]
Abstract
Considerable evidence indicates that adenosine A(2A) receptors (A(2A)Rs) modulate cholinergic neurotransmission, nicotinic acetylcholine receptor (nAChR) function, and nicotine-induced behavioural effects. To explore the interaction between A(2A) and nAChRs, we examined if the complete genetic deletion of adenosine A(2A)Rs in mice induces compensatory alterations in the binding of different nAChR subtypes, and whether the long-term effects of nicotine on nAChR regulation are altered in the absence of the A(2A)R gene. Quantitative autoradiography was used to measure cytisine-sensitive [¹²⁵I]epibatidine and [¹²⁵I]α-bungarotoxin binding to α4β2* and α7 nAChRs, respectively, in brain sections of drug-naïve (n = 6) or nicotine treated (n = 5-7), wild-type and adenosine A(2A)R knockout mice. Saline or nicotine (7.8 mg/kg/day; free-base weight) were administered to male CD1 mice via subcutaneous osmotic minipumps for a period of 14 days. Blood plasma levels of nicotine and cotinine were measured at the end of treatment. There were no compensatory developmental alterations in nAChR subtype distribution or density in drug-naïve A(2A)R knockout mice. In nicotine treated wild-type mice, both α4β2* and α7 nAChR binding sites were increased compared with saline treated controls. The genetic ablation of adenosine A(2A)Rs prevented nicotine-induced upregulation of α7 nAChRs, without affecting α4β2* receptor upregulation. This selective effect was observed at plasma levels of nicotine that were within the range reported for smokers (10-50 ng ml⁻¹). Our data highlight the involvement of adenosine A(2A)Rs in the mechanisms of nicotine-induced α7 nAChR upregulation, and identify A(2A)Rs as novel pharmacological targets for modulating the long-term effects of nicotine on α7 receptors.
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Affiliation(s)
- Athanasios Metaxas
- Sleep, Chronobiology & Addiction Group, Department of Biochemistry & Physiology, Faculty of Health and Medical Sciences, Institute of Health & Medical Sciences, University of Surrey, UK.
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24
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The volitional nature of nicotine exposure alters anandamide and oleoylethanolamide levels in the ventral tegmental area. Neuropsychopharmacology 2013; 38:574-84. [PMID: 23169348 PMCID: PMC3572454 DOI: 10.1038/npp.2012.210] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cannabinoid-1 receptors (CB(1)) have an important role in nicotine reward and their function is disrupted by chronic nicotine exposure, suggesting nicotine-induced alterations in endocannabinoid (eCB) signaling. However, the effects of nicotine on brain eCB levels have not been rigorously evaluated. Volitional intake of nicotine produces physiological and behavioral effects distinct from forced drug administration, although the mechanisms underlying these effects are not known. This study compared the effects of volitional nicotine self-administration (SA) and forced nicotine exposure (yoked administration (YA)) on levels of eCBs and related neuroactive lipids in the ventral tegmental area (VTA) and other brain regions. Brain lipid levels were indexed both by in vivo microdialysis in the VTA and lipid extractions from brain tissues. Nicotine SA, but not YA, reduced baseline VTA dialysate oleoylethanolamide (OEA) levels relative to nicotine-naïve controls, and increased anandamide (AEA) release during nicotine intake. In contrast, all nicotine exposure paradigms increased VTA dialysate 2-arachidonoyl glycerol (2-AG) levels. Thus, nicotine differentially modulates brain lipid (2-AG, AEA, and OEA) signaling, and these modulations are influenced by the volitional nature of the drug exposure. Corresponding bulk tissue analysis failed to identify these lipid changes. Nicotine exposure had no effect on fatty acid amide hydrolase activity in the VTA, suggesting that changes in AEA and OEA signaling result from alterations in their nicotine-induced biosynthesis. Both CB(1) (by AEA and 2-AG) and non-CB(1) (by OEA) targets can alter the excitability and activity of the dopaminergic neurons in the VTA. Collectively, these findings implicate disrupted lipid signaling in the motivational effects of nicotine.
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Metaxas A, Keyworth H, Yoo J, Chen Y, Kitchen I, Bailey A. The stereotypy-inducing and OCD-like effects of chronic 'binge' cocaine are modulated by distinct subtypes of nicotinic acetylcholine receptors. Br J Pharmacol 2013; 167:450-64. [PMID: 22568685 DOI: 10.1111/j.1476-5381.2012.02023.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE High rates of cigarette smoking occur in cocaine-dependent individuals, reflecting an involvement of nicotinic acetylcholine receptors (nAChRs) in cocaine-elicited behaviour. This study was designed to assess the contribution of different nAChR subtypes to the behavioural and neurochemical effects of chronic cocaine treatment. EXPERIMENTAL APPROACH Cocaine (15 mg·kg(-1) , i.p.) was administered to male C57BL/6J mice in a chronic 'binge' paradigm, with and without the coadministration of the α7 preferring nAChR antagonist methyllycaconitine (MLA; 5 mg·kg(-1) , i.p.) or the β2* nAChR antagonist dihydro-β-erythroidine (DHβE; 2 mg·kg(-1) , i.p.). Quantitative autoradiography was used to examine the effect of cocaine exposure on α7 and α4β2* nAChRs, and on the high-affinity choline transporter. KEY RESULTS MLA+cocaine administration induced an intense self-grooming behaviour, indicating a likely role for α7 nAChRs in modulating this anxiogenic, compulsive-like effect of cocaine. In the major island of Calleja, a key area of action for neuroleptics, MLA+cocaine reduced choline transporter binding compared with cocaine (with or without DHβE) administration. DHβE treatment prevented the induction of stereotypy sensitisation to cocaine but prolonged locomotor sensitisation, implicating heteromeric β2* nAChRs in the neuroadaptations mediating cocaine-induced behavioural sensitisation. 'Binge' cocaine treatment region-specifically increased α4β2* nAChR binding in the midbrain dopaminergic regions: ventral tegmental area and substantia nigra pars compacta. CONCLUSIONS AND IMPLICATIONS We have shown a differential, subtype-selective, contribution of nAChRs to the behavioural and neurochemical sequelae of chronic cocaine administration. These data support the clinical utility of targeting specific nAChR subtypes for the alleviation of cocaine-abuse symptomatology.
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Affiliation(s)
- A Metaxas
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, Institute of Health and Medical Sciences, University of Surrey, Guildford, UK.
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26
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Naldi I, Bisulli F, Vignatelli L, Licchetta L, Pittau F, Di Vito L, Mostacci B, Menghi V, Provini F, Montagna P, Tinuper P. Tobacco habits in nocturnal frontal lobe epilepsy. Epilepsy Behav 2013; 26:114-7. [PMID: 23246147 DOI: 10.1016/j.yebeh.2012.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/27/2012] [Accepted: 10/11/2012] [Indexed: 11/20/2022]
Abstract
The beneficial effect of nicotine has been reported in autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) patients, but not tested in sporadic cases. Recently, a nicotine defect in the arousal pathway has been hypothesized even in sporadic NFLE patients and their relatives. This case-control family study was designed to test whether NFLE subjects were more likely to use tobacco than controls, as an indirect marker of cholinergic arousal system dysregulation. At least four relatives were included for each NFLE proband and control. Each subject was questioned about tobacco habits; 434 individuals were recruited. Moreover, we compared NFLE patients with age- and sex-matched controls to determine whether they are more likely to use tobacco. We found a slightly higher trend of tobacco use in NFLE probands compared to that in control subjects; we did not find any significant difference in the distribution of tobacco use among NFLE group compared to that in the control group.
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Affiliation(s)
- Ilaria Naldi
- IRCCS Istituto delle Scienze Neurologiche Bologna, and Dipartimento di ScienzeBiomediche e NeuroMotorie, Alma Mater Studiorum Università di Bologna, Bologna, Italy
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27
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Abstract
The identification and functional understanding of the neurocircuitry that mediates alcohol and drug effects that are relevant for the development of addictive behavior is a fundamental challenge in addiction research. Here we introduce an assumption-free construction of a neurocircuitry that mediates acute and chronic drug effects on neurotransmitter dynamics that is solely based on rodent neuroanatomy. Two types of data were considered for constructing the neurocircuitry: (1) information on the cytoarchitecture and neurochemical connectivity of each brain region of interest obtained from different neuroanatomical techniques; (2) information on the functional relevance of each region of interest with respect to alcohol and drug effects. We used mathematical data mining and hierarchical clustering methods to achieve the highest standards in the preprocessing of these data. Using this approach, a dynamical network of high molecular and spatial resolution containing 19 brain regions and seven neurotransmitter systems was obtained. Further graph theoretical analysis suggests that the neurocircuitry is connected and cannot be separated into further components. Our analysis also reveals the existence of a principal core subcircuit comprised of nine brain regions: the prefrontal cortex, insular cortex, nucleus accumbens, hypothalamus, amygdala, thalamus, substantia nigra, ventral tegmental area and raphe nuclei. Finally, by means of algebraic criteria for synchronizability of the neurocircuitry, the suitability for in silico modeling of acute and chronic drug effects is indicated. Indeed, we introduced as an example a dynamical system for modeling the effects of acute ethanol administration in rats and obtained an increase in dopamine release in the nucleus accumbens-a hallmark of drug reinforcement-to an extent similar to that seen in numerous microdialysis studies. We conclude that the present neurocircuitry provides a structural and dynamical framework for large-scale mathematical models and will help to predict chronic drug effects on brain function.
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Affiliation(s)
- Hamid R. Noori
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim; University of Heidelberg; Mannheim; Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim; University of Heidelberg; Mannheim; Germany
| | - Anita C. Hansson
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim; University of Heidelberg; Mannheim; Germany
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Gould RW, Garg PK, Garg S, Nader MA. Effects of nicotinic acetylcholine receptor agonists on cognition in rhesus monkeys with a chronic cocaine self-administration history. Neuropharmacology 2012; 64:479-88. [PMID: 22921923 DOI: 10.1016/j.neuropharm.2012.08.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/09/2012] [Accepted: 08/09/2012] [Indexed: 01/08/2023]
Abstract
Cocaine use is associated with impaired cognitive function, which may negatively impact treatment outcomes. One pharmacological strategy to improve cognition involves nicotinic acetylcholine receptor (nAChR) stimulation. However, the effects of chronic cocaine exposure on nAChR distribution and function have not been characterized. Thus, one goal of this study was to examine nAChR availability in rhesus monkeys with an extensive cocaine self-administration history (n = 4; ~6 years, mean intake, 1463 mg/kg) compared to age-matched cocaine-naive control monkeys (n = 5). Using [¹¹C]-nicotine and positron emission tomography (PET) imaging, cocaine-experienced monkeys showed significantly higher receptor availability in the hippocampus compared to cocaine-naive monkeys. A second goal was to examine the effects of nAChR agonists on multiple domains of cognitive performance in these same monkeys. For these studies, working memory was assessed using a delayed match-to-sample (DMS) task, associative learning and behavioral flexibility using stimulus discrimination and reversal learning tasks. When administered acutely, the nonselective high-efficacy agonist nicotine, the low-efficacy α4β2* subtype-selective agonist varenicline and the high-efficacy α7 subtype-selective agonist, PNU-282987 significantly improved DMS performance in both cocaine-naive and cocaine-experienced monkeys. Individual doses of nicotine and varenicline that engendered maximum cognitive enhancing effects on working memory did not affect discrimination or reversal learning, while PNU-282987 disrupted reversal learning in the cocaine-naive monkeys. These findings indicate that a cocaine self-administration history influenced nAChR distribution and the effects of nAChR agonists on cognitive performance, including a reduced sensitivity to the disrupting effects on reversal learning. The cognitive enhancing effects of nAChR agonists may be beneficial in combination with behavioral treatments for cocaine addiction. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Robert W Gould
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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29
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Alpha7-nicotinic receptors modulate nicotine-induced reinforcement and extracellular dopamine outflow in the mesolimbic system in mice. Psychopharmacology (Berl) 2012; 220:1-14. [PMID: 21901321 DOI: 10.1007/s00213-011-2422-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 07/16/2011] [Indexed: 10/17/2022]
Abstract
RATIONALE Nicotine is the main addictive component of tobacco and modifies brain function via its action on neuronal acetylcholine nicotinic receptors (nAChRs). The mesolimbic dopamine (DA) system, where neurons of the ventral tegmental area (VTA) project to the nucleus accumbens (ACb), is considered a core site for the processing of nicotine's reinforcing properties. However, the precise subtypes of nAChRs that mediate the rewarding properties of nicotine and that contribute to the development of addiction remain to be identified. OBJECTIVES We investigated the role of the nAChRs containing the α7 nicotinic subunit (α7 nAChRs) in the reinforcing properties of nicotine within the VTA and in the nicotine-induced changes in ACb DA outflow in vivo. METHODS We performed intra-VTA self-administration and microdialysis experiments in genetically modified mice lacking the α7 nicotinic subunit or after pharmacological blockade of α7 nAChRs in wild-type mice. RESULTS We show that the reinforcing properties of nicotine within the VTA are lower in the absence or after pharmacological blockade of α7 nAChRs. We also report that nicotine-induced increases in ACb DA extracellular levels last longer in the absence of these receptors, suggesting that α7 nAChRs regulate the action of nicotine on DA levels over time. CONCLUSIONS The present results reveal new insights for the role of α7 nAChRs in modulating the action of nicotine within the mesolimbic circuit. These receptors appear to potentiate the reinforcing action of nicotine administered into the VTA while regulating its action over time on DA outflow in the ACb.
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30
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Yan Y, Pushparaj A, Gamaleddin I, Steiner RC, Picciotto MR, Roder J, Le Foll B. Nicotine-taking and nicotine-seeking in C57Bl/6J mice without prior operant training or food restriction. Behav Brain Res 2012; 230:34-9. [PMID: 22326373 DOI: 10.1016/j.bbr.2012.01.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 01/17/2012] [Accepted: 01/23/2012] [Indexed: 11/25/2022]
Abstract
The ability to examine genetically engineered mice in a chronic intravenous (IV) nicotine self-administration paradigm will be a powerful tool for investigating the contribution of specific genes to nicotine reinforcement and more importantly, to relapse behavior. Here we describe a reliable model of nicotine-taking and -seeking behavior in male C57BL/6J mice without prior operant training or food restriction. Mice were allowed to self-administer either nicotine (0.03mg/kg/infusion) or saline in 2-h daily sessions under fixed ratio 1 (FR1) followed by FR2 schedules of reinforcement. In the nicotine group, a dose-response curve was measured after the nose-poke behavior stabilized. Subsequently, nose-poke behavior was extinguished and ability of cue presentations, priming injections of nicotine, or intermittent footshock to reinstate responding was assessed in both groups. C57BL/6J mice given access to nicotine exhibited high levels of nose-poke behavior and self-administered a high number of infusions as compared to mice given access to saline. After this acquisition phase, changing the unit-dose of nicotine resulted in a flat dose-response curve for nicotine-taking and subsequently reinstatement of nicotine-seeking behavior was achieved by both nicotine-associated light cue presentation and intermittent footshock. Nicotine priming injections only triggered significant reinstatement on the second consecutive day of priming. In contrast, mice previously trained to self-administer saline did not increase their responding under those conditions. These results demonstrate the ability to produce nicotine-taking and nicotine-seeking behavior in naive C57BL/6J mice without both prior operant training and food restriction. Future work will utilize these models to evaluate nicotine-taking and relapsing behavior in genetically-altered mice.
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Affiliation(s)
- Yijin Yan
- Translational Addiction Research Laboratory, Neuroscience Department, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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31
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Abstract
Tobacco use is a major health problem, and nicotine is the main addictive component. Nicotine binds to nicotinic acetylcholine receptors (nAChR) to produce its initial effects. The nAChRs subtypes are composed of five subunits that can form in numerous combinations with varied functional and pharmacological characteristics. Diverse psychopharmacological effects contribute to the overall process of nicotine addiction, but two general neural systems are emerging as critical for the initiation and maintenance of tobacco use. Mesocorticolimbic circuitry that includes the dopaminergic pathway originating in the ventral tegmental area and projecting to the nucleus accumbens is recognized as vital for reinforcing behaviors during the initiation of nicotine addiction. In this neural system β2, α4, and α6 are the most important nAChR subunits underlying the rewarding aspects of nicotine and nicotine self-administration. On the other hand, the epithalamic habenular complex and the interpeduncular nucleus, which are connected via the fasciculus retroflexus, are critical contributors regulating nicotine dosing and withdrawal symptoms. In this case, the α5 and β4 nAChR subunits have critical roles in combination with other subunits. In both of these neural systems, particular nAChR subtypes have roles that contribute to the overall nicotine addiction process.
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Affiliation(s)
- John A Dani
- Department of Neuroscience, Center on Addiction, Learning, Memory, Baylor College of Medicine, Houston, Texas 77030-3498, USA
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32
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Abstract
Nicotine is the principal addictive component that drives continued tobacco use despite users' knowledge of the harmful consequences. The initiation of addiction involves the mesocorticolimbic dopamine system, which contributes to the processing of rewarding sensory stimuli during the overall shaping of successful behaviors. Acting mainly through nicotinic receptors containing the α4 and β2 subunits, often in combination with the α6 subunit, nicotine increases the firing rate and the phasic bursts by midbrain dopamine neurons. Neuroadaptations arise during chronic exposure to nicotine, producing an altered brain condition that requires the continued presence of nicotine to be maintained. When nicotine is removed, a withdrawal syndrome develops. The expression of somatic withdrawal symptoms depends mainly on the α5, α2, and β4 (and likely α3) nicotinic subunits involving the epithalamic habenular complex and its targets. Thus, nicotine taps into diverse neural systems and an array of nicotinic acetylcholine receptor (nAChR) subtypes to influence reward, addiction, and withdrawal.
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Affiliation(s)
- Mariella De Biasi
- Department of Neuroscience, Center on Addiction, Learning, Memory, Baylor College of Medicine, Houston, Texas 77030, USA.
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The necessity of α4* nicotinic receptors in nicotine-driven behaviors: dissociation between reinforcing and motor effects of nicotine. Neuropsychopharmacology 2011; 36:1505-17. [PMID: 21430644 PMCID: PMC3096818 DOI: 10.1038/npp.2011.35] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Here we utilize a mouse line with a targeted deletion of the α4 subunit (α4-/- mice), to investigate the role of α4* nAChRs in reinforcing and locomotor effects of nicotine. Within a conditioned place preference paradigm, both α4-/- mice and wild-type (WT) littermates showed a similar place preference to nicotine (0.5 mg/kg i.p.) conditioning. When assessed for operant intravenous self-administration of nicotine (0.05 mg/kg/infusion), α4-/- mice did not differ from their WT littermates in self-administration behavior. To further examine a modulatory role for α4* nAChRs in the reinforcing effects of nicotine, a transgenic mouse with a point mutation of the α4 subunit (α4-S248F) that renders increased sensitivity to low dose nicotine, was assessed for nicotine self-administration over a range of doses. At higher doses examined (0.05 and 0.07 mg/kg/infusion) there was no difference in intravenous nicotine self-administration; however, when mice were offered a lower dose of nicotine (0.03 mg/kg/infusion), α4-S248F mice showed greater nicotine intake than controls. Acute administration of 0.5 mg/kg nicotine caused significant locomotor depression in WT mice but α4-/- mice instead showed significant hyperactivity. Following chronic, intermittent administration of this dose of nicotine only WT mice displayed significant tolerance. Analogous experiments utilizing administration of the nicotinic antagonist mecamylamine in WT mice confirmed a dissociation between the putative nicotinic receptor subtypes required for mediating psychomotor and reinforcing effects of nicotine. These data demonstrate a necessary role for α4* nAChRs in the locomotor depressant effect of nicotine but not the reinforcing effects that support ongoing self-administration of nicotine.
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34
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Fowler CD, Kenny PJ. Intravenous nicotine self-administration and cue-induced reinstatement in mice: effects of nicotine dose, rate of drug infusion and prior instrumental training. Neuropharmacology 2011; 61:687-98. [PMID: 21640128 DOI: 10.1016/j.neuropharm.2011.05.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 05/11/2011] [Accepted: 05/15/2011] [Indexed: 01/08/2023]
Abstract
Intravenous nicotine self-administration is the most direct measure of nicotine reinforcement in laboratory animals, but this procedure has proven difficult to establish in mice. We found that stable responding for nicotine in C57BL6/J mice was facilitated by prior instrumental training for food reward, initial exposure of mice to a lower unit dose of nicotine (0.03 mg kg(-1) per infusion) before access to higher doses, a slower rate of drug delivery (3-s versus 1-s infusion), consistency in schedule of daily testing, and low extraneous noise during testing. Under these conditions, we found that mice lever-pressed for nicotine (0.03-0.4 mg kg(-1) per infusion; 60-min test sessions) under a fixed-ratio 5 time-out 20-s (FR5TO20) reinforcement schedule and consumed the drug according to an inverted 'U'-shaped dose-response curve. Mice switched their responding onto a previously non-reinforced lever to continue earning nicotine infusions when the active/inactive lever assignment was reversed. The nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine decreased responding for nicotine, but not food rewards, verifying that nAChRs regulate nicotine self-administration in mice. The cue-light paired with nicotine delivery did not support responding when delivered independently of nicotine infusions, further verifying that mice responded selectivity for the drug. Nicotine-seeking responses extinguished when nicotine infusions and the cue-light were withheld, and exposure to the cue-light reinstated responding. Finally, mice without prior instrumental food training acquired stable responding for nicotine under the FR5TO20 schedule, but required a greater number of sessions. These data demonstrate that nicotine is an effective reinforcer in mice and establish conditions under which the drug is reliably self-administered by mice.
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Affiliation(s)
- Christie D Fowler
- Department of Molecular Therapeutics, The Scripps Research Institute-Scripps Florida, Jupiter, FL 33458, USA
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