Donepezil, an acetylcholinesterase inhibitor, attenuates nicotine self-administration and reinstatement of nicotine seeking in rats

Targeting GLP-1 receptors to reduce nicotine use disorder: Preclinical and clinical evidence

Nicotine use disorder (NUD) remains a leading cause of preventable death in the U.S. Unfortunately, current FDA-approved pharmacotherapies for smoking cessation have limited efficacy and are associated with high rates of relapse. One major barrier to long-term smoking abstinence is body weight gain during withdrawal. Nicotine withdrawal-induced body weight gain can also lead to development of chronic disease states like obesity and type II diabetes mellitus. Therefore, it is critical to identify novel pharmacotherapies for NUD that decrease relapse and nicotine withdrawal symptoms including body weight gain. Recent studies demonstrate that glucagon-like peptide-1 receptor (GLP-1R) agonists attenuate voluntary nicotine taking and seeking and prevent withdrawal-induced hyperphagia and body weight gain. Emerging evidence also suggests that GLP-1R agonists improve cognitive deficits, as well as depressive- and anxiety-like behaviors, which contribute to smoking relapse during withdrawal. While further studies are necessary to fully characterize the effects of GLP-1R agonists on NUD and understand the mechanisms by which GLP-1R agonists decrease nicotine withdrawal-mediated behaviors, the current literature supports GLP-1R-based approaches to treating NUD.

PYY3-36 infused systemically or directly into the VTA attenuates fentanyl seeking in male rats

More effective treatments for fentanyl use disorder are urgently needed. An emerging literature indicates that glucagon-like peptide-1 receptor (GLP-1R) agonists attenuate voluntary opioid taking and seeking in rodents. However, GLP-1R agonists produce adverse malaise-like effects that may limit patient compliance. Recently, we developed a dual agonist of GLP-1Rs and neuropeptide Y2 receptors (Y2Rs) that attenuates fentanyl taking and seeking at doses that do not produce malaise-like effects in opioid-experienced rats. Whether activating Y2Rs alone is sufficient to reduce opioid taking and seeking, however, is not known. Here, we investigated the efficacy of the Y2R ligand PYY3-36 to reduce fentanyl self-administration and the reinstatement of fentanyl-seeking behavior, a model of relapse in humans. Male rats were allowed to self-administer fentanyl (2.5 μg/kg, i.v.) for 21 days on a fixed-ratio 5 (FR5) schedule of reinforcement. Rats were then pretreated with vehicle or PYY3-36 (50 μg/kg s.c.; 0.1 and 1.0 μg/100 nL intra-VTA) prior to fentanyl self-administration test sessions. There were no effects of systemic or intra-VTA PYY3-36 on intravenous fentanyl self-administration. Opioid taking was then extinguished. Prior to subsequent reinstatement test sessions, rats were pretreated with vehicle or PYY3-36 (50 μg/kg s.c.; 0.1 and 1.0 μg/100 nL intra-VTA). Both systemic and intra-VTA administration of PYY3-36 attenuated fentanyl reinstatement in male rats at doses that did not affect food intake or produce adverse malaise-like effects. These findings indicate that Y2R agonism alone is sufficient to decrease fentanyl-seeking behavior during abstinence in opioid-experienced rats and further support strategies aimed at targeting Y2Rs for treating opioid use disorders.

Folic acid supplementation improved nicotine withdrawal-induced of memory loss via affecting oxidative status, inflammatory response, cholinergic activity, BDNF and amyloid-B in adolescent male rat

BACKGROUND

The present study aimed to assess whether folic acid (FA) have potential to prevent memory impairment caused by nicotine (Nico) withdrawal in adolescent male rats.

METHODS AND MATERIALS

The experiments were divided into 7 groups: 1) vehicle, 2) Nico (Nico 2 mg/kg injection from 21 to 42 days of ages), 3-5) Nico FA5/10/15 mg/kg (received Nico from 21 to 42 days of ages and received FA at three doses 5, 10 and 15 mg/kg 43-63 days of ages), and 6) received normal saline from 21 to 42 days of age after that received FA 15 mg/kg by oral gavage from 43 to 63 days of age. At 64-69 days of ages, behavioral tests related to memory including Morris Water Maze (MWM) and Object Recognition Test (ORT) were performed and related biochemical analysis including the hippocampal levels of oxidative stress markers, inflammatory indices, brain-derived neurotrophic factor (BDNF), nitrite, amyloid-B and acetylcholinesterase [1] were measured.

RESULTS

Results showed that nicotine exposure in adolescence followed by withdrawal dramatically impaired learning and memory performance along with affecting a variety of biochemical markers in the hippocampal tissues. In addition, it was observed that administration of FA significantly ameliorated Nico withdrawal-induced adverse effects through restoration of the mentioned biochemical disturbances.

CONCLUSION

The present study and other relevant researches demonstrated that FA as a well-known, inexpensive, and safe supplement has strong potential to either prevent or ameliorate the detrimental effect of Nico withdrawal. However, further investigation is required to be more elucidated the precise mechanisms underlying memory impairment-induced by Nico withdrawal.

Liraglutide attenuates nicotine self-administration as well as nicotine seeking and hyperphagia during withdrawal in male and female rats

RATIONALE

Nicotine cessation is associated with increased consumption of highly palatable foods and body weight gain in most smokers. Concerns about body weight gain are a major barrier to maintaining long-term smoking abstinence, and current treatments for nicotine use disorder (NUD) delay, but do not prevent, body weight gain during abstinence. Glucagon-like peptide-1 receptor (GLP-1R) agonists reduce food intake and are FDA-approved for treating obesity. However, the effects of GLP-1R agonist monotherapy on nicotine seeking and withdrawal-induced hyperphagia are unknown.

OBJECTIVES

We screened the efficacy of the long-lasting GLP-1R agonist liraglutide to reduce nicotine-mediated behaviors including voluntary nicotine taking, as well as nicotine seeking and hyperphagia during withdrawal.

METHODS

Male and female rats self-administered intravenous nicotine (0.03 mg/kg/inf) for ~21 days. Daily liraglutide administration (25 μg/kg, i.p.) started on the last self-administration day and continued throughout the extinction and reinstatement phases of the experiment. Once nicotine taking was extinguished, the reinstatement of nicotine-seeking behavior was assessed after an acute priming injection of nicotine (0.2 mg/kg, s.c.) and re-exposure to conditioned light cues. Using a novel model of nicotine withdrawal-induced hyperphagia, intake of a high fat diet (HFD) was measured during home cage abstinence in male and female rats with a history of nicotine self-administration.

RESULTS

Liraglutide attenuated nicotine self-administration and reinstatement in male and female rats. Repeated liraglutide attenuated withdrawal-induced hyperphagia and body weight gain in male and female rats at a dose that was not associated with malaise-like effects.

CONCLUSIONS

These findings support further studies investigating the translational potential of GLP-1R agonists to treat NUD.

Paternal nicotine taking elicits heritable sex-specific phenotypes that are mediated by hippocampal Satb2

Nicotine intake, whether through tobacco smoking or e-cigarettes, remains a global health concern. An emerging preclinical literature indicates that parental nicotine exposure produces behavioral, physiological, and molecular changes in subsequent generations. However, the heritable effects of voluntary parental nicotine taking are unknown. Here, we show increased acquisition of nicotine taking in male and female offspring of sires that self-administered nicotine. In contrast, self-administration of sucrose and cocaine were unaltered in male and female offspring suggesting that the intergenerational effects of paternal nicotine taking may be reinforcer specific. Further characterization revealed memory deficits and increased anxiety-like behaviors in drug-naive male, but not female, offspring of nicotine-experienced sires. Using an unbiased, genome-wide approach, we discovered that these phenotypes were associated with decreased expression of Satb2, a transcription factor known to play important roles in synaptic plasticity and memory formation, in the hippocampus of nicotine-sired male offspring. This effect was sex-specific as no changes in Satb2 expression were found in nicotine-sired female offspring. Finally, increasing Satb2 levels in the hippocampus prevented the escalation of nicotine intake and rescued the memory deficits associated with paternal nicotine taking in male offspring. Collectively, these findings indicate that paternal nicotine taking produces heritable sex-specific molecular changes that promote addiction-like phenotypes and memory impairments in male offspring.

A novel dual agonist of glucagon-like peptide-1 receptors and neuropeptide Y2 receptors attenuates fentanyl taking and seeking in male rats

There has been a dramatic increase in illicit fentanyl use in the United States over the last decade. In 2018, more than 31,000 overdose deaths involved fentanyl or fentanyl analogs, highlighting an urgent need to identify effective treatments for fentanyl use disorder. An emerging literature shows that glucagon-like peptide-1 receptor (GLP-1R) agonists attenuate the reinforcing efficacy of drugs of abuse. However, the effects of GLP-1R agonists on fentanyl-mediated behaviors are unknown. The first goal of this study was to determine if the GLP-1R agonist exendin-4 reduced fentanyl self-administration and the reinstatement of fentanyl-seeking behavior, an animal model of relapse, in rats. We found that systemic exendin-4 attenuated fentanyl taking and seeking at doses that also produced malaise-like effects in rats. To overcome these adverse effects and enhance the clinical potential of GLP-1R agonists, we recently developed a novel dual agonist of GLP-1Rs and neuropeptide Y2 receptors (Y2Rs), GEP44, that does not produce nausea-like behavior in drug-naïve rats or emesis in drug-naïve shrews. The second goal of this study was to determine if GEP44 reduced fentanyl self-administration and reinstatement with fewer adverse effects compared to exendin-4 alone. In contrast to exendin-4, GEP44 attenuated opioid taking and seeking at a dose that did not suppress food intake or produce adverse malaise-like effects in fentanyl-experienced rats. Taken together, these findings indicate a novel role for GLP-1Rs and Y2Rs in fentanyl reinforcement and highlight a potential new therapeutic approach to treating opioid use disorders.

Vitamin D3 reduces hippocampal NR2A and anxiety in nicotine withdrawal mice

Nicotine withdrawal symptoms, mainly anxiety, cause high level of relapse rate after quitting smoking. Vitamin D supplementation has shown its potential for the prevention and treatment of anxiety disorders; however, neurobiological studies about the effect of vitamin D on nicotine withdrawal-induced anxiety are limited. To investigate the effect and molecular mechanism of vitamin D3 supplement by dietary on anxiety-like behavior during nicotine withdrawal, male C57/BL6 mice were divided into four groups: vehicle, nicotine only, vitamin D3 only, and nicotine plus vitamin D3. Mice were administrated with nicotine in drinking water (200 µg/mL), and vitamin D3 in feed for 6 weeks. During nicotine withdrawal, vitamin D3-treated mice showed significantly less anxiety-like behavior by an open-field test and marble buried test that performed an increase in the duration of the central zone and a decrease buried marble, respectively. Moreover, vitamin D3 supplementation attenuated the hippocampal NR2A expression on both protein and mRNA levels in nicotine and vitamin D3-treated mice. Our data showed that dietary supplementation with vitamin D3 ameliorated nicotine withdrawal-induced anxiety, which may be related to downregulation of NR2A expression in hippocampus. Vitamin D3 may provide a new dietary intervention with the easy access for smoking cessation.

More than Smoke and Patches: The Quest for Pharmacotherapies to Treat Tobacco Use Disorder

Tobacco use is a persistent public health issue. It kills up to half its users and is the cause of nearly 90% of all lung cancers. The main psychoactive component of tobacco is nicotine, primarily responsible for its abuse-related effects. Accordingly, most pharmacotherapies for smoking cessation target nicotinic acetylcholine receptors (nAChRs), nicotine's major site of action in the brain. The goal of the current review is twofold: first, to provide a brief overview of the most commonly used behavioral procedures for evaluating smoking cessation pharmacotherapies and an introduction to pharmacokinetic and pharmacodynamic properties of nicotine important for consideration in the development of new pharmacotherapies; and second, to discuss current and potential future pharmacological interventions aimed at decreasing tobacco use. Attention will focus on the potential for allosteric modulators of nAChRs to offer an improvement over currently approved pharmacotherapies. Additionally, given increasing public concern for the potential health consequences of using electronic nicotine delivery systems, which allow users to inhale aerosolized solutions as an alternative to smoking tobacco, an effort will be made throughout this review to address the implications of this relatively new form of nicotine delivery, specifically as it relates to smoking cessation. SIGNIFICANCE STATEMENT: Despite decades of research that have vastly improved our understanding of nicotine and its effects on the body, only a handful of pharmacotherapies have been successfully developed for use in smoking cessation. Thus, investigation of alternative pharmacological strategies for treating tobacco use disorder remains active; allosteric modulators of nicotinic acetylcholine receptors represent one class of compounds currently under development for this purpose.

Advances in smoking cessation pharmacotherapy: Non-nicotinic approaches in animal models

The landscape of worldwide tobacco use is changing, with a decrease in traditional smoking and an exponential rise in electronic cigarette use. No new nicotine cessation pharmacotherapies have come to market in the last 10 years. The current therapies that have been approved by the United States Food and Drug Administration for nicotine cessation include nicotine replacement therapy, varenicline, a nicotinic acetylcholine receptor partial agonist, and the atypical antidepressant bupropion. Nicotine replacement therapy and varenicline both act on nicotinic acetylcholine receptors. Bupropion inhibits the dopamine transporter, the norepinephrine transporter, and the nicotinic acetylcholine receptors to inhibit smoking behavior. Notwithstanding these treatments, rates of successful nicotine cessation in clinical trials remain low. Recent pharmacological approaches to improve nicotine cessation rates in animal models have turned their focus away from activating nicotinic acetylcholine receptors. The present review focuses on such pharmacological approaches, including nicotine vaccines, anti-nicotine antibodies, nicotine-degrading enzymes, cannabinoids, and metformin. Both immunopharmacological and enzymatic approaches rely on restricting and degrading nicotine within the periphery, thus preventing psychoactive effects of nicotine on the central nervous system. In contrast, pharmacologic inhibition of the enzymes which degrade nicotine could affect smoking behavior. Cannabinoid receptor agonists and antagonists interact with the dopamine reward pathway and show efficacy in reducing nicotine addiction-like behaviors in preclinical studies. Metformin is currently approved by the Food and Drug Administration for the treatment of diabetes. It activates specific intracellular kinases that may protect against the lower metabolism, higher oxidation, and inflammation that are associated with nicotine withdrawal. Further studies are needed to investigate non-nicotinic targets to improve the treatment of tobacco use disorder. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.

Neurobiological and Neurophysiological Mechanisms Underlying Nicotine Seeking and Smoking Relapse

Tobacco-related morbidity and mortality continue to be a significant public health concern. Unfortunately, current FDA-approved smoking cessation pharmacotherapies have limited efficacy and are associated with high rates of relapse. Therefore, a better understanding of the neurobiological and neurophysiological mechanisms that promote smoking relapse is needed to develop novel smoking cessation medications. Here, we review preclinical studies focused on identifying the neurotransmitter and neuromodulator systems that mediate nicotine relapse, often modeled in laboratory animals using the reinstatement paradigm, as well as the plasticity-dependent neurophysiological mechanisms that facilitate nicotine reinstatement. Particular emphasis is placed on how these neuroadaptations relate to smoking relapse in humans. We also highlight a number of important gaps in our understanding of the neural mechanisms underlying nicotine reinstatement and critical future directions, which may lead toward the development of novel, target pharmacotherapies for smoking cessation.

Neuropeptide systems and new treatments for nicotine addiction

RATIONALE

The mildly euphoric and cognitive enhancing effects of nicotine play a role in the initiation of smoking, while dysphoria and anxiety associated with smoking cessation contribute to relapse. After the acute withdrawal phase, smoking cues, a few cigarettes (i.e., lapse), and stressors can cause relapse. Human and animal studies have shown that neuropeptides play a critical role in nicotine addiction.

OBJECTIVES

The goal of this paper is to describe the role of neuropeptide systems in the initiation of nicotine intake, nicotine withdrawal, and the reinstatement of extinguished nicotine seeking.

RESULTS

The reviewed studies indicate that several drugs that target neuropeptide systems diminish the rewarding effects of nicotine by preventing the activation of dopaminergic systems. Other peptide-based drugs diminish the hyperactivity of brain stress systems and diminish withdrawal-associated symptom severity. Blockade of hypocretin-1 and nociceptin receptors and stimulation of galanin and neurotensin receptors diminishes the rewarding effects of nicotine. Both corticotropin-releasing factor type 1 and kappa-opioid receptor antagonists diminish dysphoria and anxiety-like behavior associated with nicotine withdrawal and inhibit stress-induced reinstatement of nicotine seeking. Furthermore, blockade of vasopressin 1b receptors diminishes dysphoria during nicotine withdrawal, and melanocortin 4 receptor blockade prevents stress-induced reinstatement of nicotine seeking. The role of neuropeptide systems in nicotine-primed and cue-induced reinstatement is largely unexplored, but there is evidence for a role of hypocretin-1 receptors in cue-induced reinstatement of nicotine seeking.

CONCLUSION

Drugs that target neuropeptide systems might decrease the euphoric effects of smoking and improve relapse rates by diminishing withdrawal symptoms and improving stress resilience.

Attenuation of nicotine taking and seeking in rats by the stoichiometry-selective alpha4beta2 nicotinic acetylcholine receptor positive allosteric modulator NS9283

RATIONALE

The rewarding and reinforcing effects of nicotine are produced, in large part, by activation of neuronal α4β2* nicotinic acetylcholine receptors (nAChRs), pentameric protein complexes comprised of different stoichiometries of α4 and β2 subunits. However, little is known about the functional role of distinct subtypes of α4β2* nAChRs in nicotine addiction.

OBJECTIVES

NS9283 represents a new class of stoichiometry-selective positive allosteric modulators (PAMs) that selectively bind to α4β2 nAChRs containing three α4 and two β2 subunits (3(α4)2(β2) nAChRs). The present experiments were designed to determine the effects of NS9283 on nicotine self-administration and the reinstatement of nicotine-seeking behavior, an animal model of smoking relapse. Parallel studies of sucrose self-administration and reinstatement were conducted in separate cohorts of rats to determine if the effects of NS9283 generalized to other reinforced behaviors.

RESULTS

Acute and repeated administration of NS9283 dose-dependently reduced nicotine self-administration and reinstatement in male Sprague Dawley rats. These effects were reinforcer specific as no effects of NS9283 on sucrose self-administration and reinstatement were noted. NS9283 also failed to substitute for nicotine in supporting self-administration behavior suggesting that, at the doses tested, NS9283 alone is not reinforcing.

CONCLUSION

Taken together, these results provide compelling evidence that stoichiometry-selective PAMs of 3(α4)2(β2) nAChRs attenuate nicotine taking and seeking in rats and suggest that targeting 3(α4)2(β2) nAChRs may represent a promising therapeutic strategy for preventing smoking relapse.

Repeated administration of an acetylcholinesterase inhibitor attenuates nicotine taking in rats and smoking behavior in human smokers

Tobacco smoking remains the leading cause of preventable death worldwide and current smoking cessation medications have limited efficacy. Thus, there is a clear need for translational research focused on identifying novel pharmacotherapies for nicotine addiction. Our previous studies demonstrated that acute administration of an acetylcholinesterase inhibitor (AChEI) attenuates nicotine taking and seeking in rats and suggest that AChEIs could be repurposed for smoking cessation. Here, we expand upon these findings with experiments designed to determine the effects of repeated AChEI administration on voluntary nicotine taking in rats as well as smoking behavior in human smokers. Rats were trained to self-administer intravenous infusions of nicotine (0.03 mg kg(-1) per 0.59 ml) on a fixed-ratio-5 schedule of reinforcement. Once rats maintained stable nicotine taking, galantamine or donepezil was administered before 10 consecutive daily nicotine self-administration sessions. Repeated administration of 5.0 mg kg(-1) galantamine and 3.0 mg kg(-1) donepezil attenuated nicotine self-administration in rats. These effects were reinforcer-specific and not due to adverse malaise-like effects of drug treatment as repeated galantamine and donepezil administration had no effects on sucrose self-administration, ad libitum food intake and pica. The effects of repeated galantamine (versus placebo) on cigarette smoking were also tested in human treatment-seeking smokers. Two weeks of daily galantamine treatment (8.0 mg (week 1) and 16.0 mg (week 2)) significantly reduced smoking rate as well as smoking satisfaction and reward compared with placebo. This translational study indicates that repeated AChEI administration reduces nicotine reinforcement in rats and smoking behavior in humans at doses not associated with tolerance and/or adverse effects.

Advances in nicotine research in Addiction Biology

The aim of Addiction Biology is to advance our understanding of the action of drugs of abuse and addictive processes via the publication of high-impact clinical and pre-clinical findings resulting from behavioral, molecular, genetic, biochemical, neurobiological and pharmacological research. As of 2013, Addiction Biology is ranked number 1 in the category of Substance Abuse journals (SCI). Occasionally, Addiction Biology likes to highlight via review important findings focused on a particular topic and recently published in the journal. The current review summarizes a number of key publications from Addiction Biology that have contributed to the current knowledge of nicotine research, comprising a wide spectrum of approaches, both clinical and pre-clinical, at the cellular, molecular, systems and behavioral levels. A number of findings from human studies have identified, using imaging techniques, alterations in common brain circuits, as well as morphological and network activity changes, associated with tobacco use. Furthermore, both clinical and pre-clinical studies have characterized a number of mechanistic targets critical to understanding the effects of nicotine and tobacco addiction. Together, these findings will undoubtedly drive future studies examining the dramatic impact of tobacco use and the development of treatments to counter nicotine dependence.

Translational Research on Nicotine Dependence

Nicotine dependence is a chronic, relapsing disorder with complex biological mechanisms underlying the motivational basis for this behavior. Although more than 70 % of current smokers express a desire to quit, most relapse within one year, underscoring the need for novel treatments. A key focus of translational research models addressing nicotine dependence has been on cross-validation of human and animal models in order to improve the predictive value of medication screening paradigms. In this chapter, we review several lines of research highlighting the utility of cross-validation models in elucidating the biological underpinnings of nicotine reward and reinforcement, identifying factors which may influence individual response to treatment, and facilitating rapid translation of findings to practice.

Neurobiological Bases of Cue- and Nicotine-induced Reinstatement of Nicotine Seeking: Implications for the Development of Smoking Cessation Medications

A better understanding of the neurobiological factors that contribute to relapse to smoking is needed for the development of efficacious smoking cessation medications. Reinstatement procedures allow the preclinical assessment of several factors that contribute to relapse in humans, including re-exposure to nicotine via tobacco smoking and the presentation of stimuli that were previously associated with nicotine administration (i.e., conditioned stimuli). This review provides an integrated discussion of the results of animal studies that used reinstatement procedures to assess the efficacy of pharmacologically targeting various neurotransmitter systems in attenuating the cue- and nicotine-induced reinstatement of nicotine seeking. The results of these animal studies have increased our understanding of the neurobiological processes that mediate the conditioned effects of stimuli that trigger reinstatement to nicotine seeking. Thus, these findings provide important insights into the neurobiological substrates that modulate relapse to tobacco smoking in humans and the ongoing search for novel efficacious smoking cessation medications.

Donepezil reverses nicotine withdrawal-induced deficits in contextual fear conditioning in C57BL/6J mice

Withdrawal from chronic nicotine is associated with cognitive deficits. Therapies that ameliorate cognitive deficits during withdrawal aid in preventing relapse during quit attempts. Withdrawal-induced deficits in contextual learning are associated with nicotinic acetylcholine receptor upregulation. The aim of the present study was to determine if the acetylcholinesterase inhibitor donepezil has the ability to reverse nicotine withdrawal-induced deficits in contextual learning. Results demonstrated that low doses of donepezil, which do not enhance contextual learning or alter locomotor activity/anxiety-related behavior, can reverse nicotine withdrawal-induced deficits in contextual learning. Thus, donepezil may have therapeutic value for ameliorating cognitive deficits associated with nicotine withdrawal and for preventing relapse.

Administration of the nicotinic acetylcholine receptor agonists ABT-089 and ABT-107 attenuates the reinstatement of nicotine-seeking behavior in rats

Current smoking cessation pharmacotherapies have modest efficacy, and most smokers relapse within the first few days after a quit attempt. Nicotine withdrawal-induced craving and cognitive impairments predict smoking relapse during abstinence and suggest that cognitive-enhancing drugs may prevent relapse. ABT-089 and ABT-107 are subtype-selective nAChR agonists that improve cognitive performance in laboratory animals. However, there are no studies examining the effects of ABT-089 and ABT-107 on nicotine self-administration and the reinstatement of nicotine-seeking behavior, an animal model of relapse in human smokers. The goal of the present study was to determine the effects of the α4β2*/α6β2* nAChR agonist ABT-089 and the α7 nAChR agonist ABT-107 on nicotine taking and seeking in rats. The effects of acute ABT-089 and ABT-107 pretreatment on nicotine self-administration and reinstatement were tested in male Sprague Dawley rats. Parallel studies of ABT-089 and ABT-107 on sucrose self-administration and reinstatement were tested in separate groups of rats to determine if the effects of these drug treatments generalized to other reinforced behaviors. Nicotine and sucrose self-administration behaviors were not altered following acute administration of ABT-089 (0, 0.12, 1.2 and 12.0mg/kg) or ABT-107 (0, 0.03 and 0.3mg/kg). In contrast, both ABT-089 and ABT-107 pretreatment dose-dependently attenuated nicotine reinstatement. These effects were reinforcer-specific as no effects of ABT-089 or ABT-107 pretreatment on sucrose seeking were noted. Taken together, these findings suggest that ABT-089 and ABT-107 do not affect nicotine consumption, but may reduce the likelihood that a smoking lapse will lead to relapse.

Optimizing treatments for nicotine dependence by increasing cognitive performance during withdrawal

INTRODUCTION

Current FDA-approved smoking cessation pharmacotherapies have limited efficacy and are associated with high rates of relapse. Therefore, there is a clear need to develop novel antismoking medications. Nicotine withdrawal is associated with cognitive impairments that predict smoking relapse. It has been proposed that these cognitive deficits are a hallmark of nicotine withdrawal that could be targeted in order to prevent smoking relapse. Thus, pharmacotherapies that increase cognitive performance during nicotine withdrawal may represent potential smoking cessation agents.

AREAS COVERED

The authors review the clinical literature demonstrating that nicotine withdrawal is associated with deficits in working memory, attention and response inhibition. They then briefly summarize different classes of compounds and strategies to increase cognitive performance during nicotine withdrawal. Particular emphasis has been placed on translational research in order to highlight areas for which there is strong rationale for pilot clinical trials of potential smoking cessation medications.

EXPERT OPINION

There is emerging evidence that supports deficits in cognitive function as a plausible nicotine withdrawal phenotype. The authors furthermore believe that the translational paradigms presented here may represent efficient and valid means for the evaluation of cognitive-enhancing medications as possible treatments for nicotine dependence.

Cognitive function during nicotine withdrawal: Implications for nicotine dependence treatment

Nicotine withdrawal is associated with deficits in neurocognitive function including sustained attention, working memory, and response inhibition. Several convergent lines of evidence suggest that these deficits may represent a core dependence phenotype and a target for treatment development efforts. A better understanding of the mechanisms underlying withdrawal-related cognitive deficits may lead to improve nicotine dependence treatment. We begin with an overview of the neurocognitive effects of withdrawal in rodent and human models, followed by discussion of the neurobehavioral mechanisms that are thought to underlie these effects. We then review individual differences in withdrawal-related neurocognitive effects including genetics, gender, and psychiatric comorbidity. We conclude with a discussion of the implications of this research for developing improved therapies, both pharmacotherapy and behavioral treatments, that target cognitive symptoms of nicotine withdrawal. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.