am4113 and Tobacco-Use-Disorder

Nicotine, the main psychoactive component of tobacco, and (-)-Δ(9)-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, play major roles in tobacco and marijuana dependence as reinforcers of drug-seeking and drug-taking behavior. Drugs that act as inverse agonists of cannabinoid CB1 receptors in the brain can attenuate the rewarding and abuse-related effects of nicotine and THC, but their clinical use is hindered by potentially serious side effects. The recently developed CB1-receptor neutral antagonists may provide an alternative therapeutic approach to nicotine and cannabinoid dependence. Here we compare attenuation of nicotine and THC reinforcement and reinstatement in squirrel monkeys by the CB1-receptor inverse agonist rimonabant and by the recently developed CB1-receptor neutral antagonist AM4113. Both rimonabant and AM4113 reduced two effects of nicotine and THC that play major roles in tobacco and marijuana dependence: (1) maintenance of high rates of drug-taking behavior, and (2) priming- or cue-induced reinstatement of drug-seeking behavior in abstinent subjects (models of relapse). In contrast, neither rimonabant nor AM4113 modified cocaine-reinforced or food-reinforced operant behavior under similar experimental conditions. However, both rimonabant and AM4113 reduced cue-induced reinstatement in monkeys trained to self-administer cocaine, suggesting the involvement of a common cannabinoid-mediated mechanism in the cue-induced reinstatement for different drugs of abuse. These findings point to CB1-receptor neutral antagonists as a new class of medications for treatment of both tobacco dependence and cannabis dependence.

Topics: Animals; Conditioning, Operant; Cues; Dronabinol; Drug-Seeking Behavior; Male; Marijuana Abuse; Nicotine; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Recurrence; Reinforcement, Psychology; Rimonabant; Saimiri; Self Administration; Tobacco Use Disorder

Multiple studies suggest a pivotal role of the endocannabinoid system in regulating the reinforcing effects of various substances of abuse. Rimonabant, a CB. Rats were trained to self-administer nicotine under a fixed-ratio 5 or progressive-ratio schedules of reinforcement. A control group was trained to self-administer food. The acute/chronic effects of AM4113 pretreatment were evaluated on nicotine taking, motivation for nicotine, and cue-, nicotine priming- and yohimbine-induced reinstatement of nicotine-seeking. The effects of AM4113 in the basal firing and bursting activity of midbrain dopamine neurons were evaluated in a separate group of animals treated with nicotine. Anxiety/depression-like effects of AM4113 and rimonabant were evaluated 24h after chronic (21 days) pretreatment (0, 1, 3, and 10mg/kg, 1/d).. AM4113 significantly attenuated nicotine taking, motivation for nicotine, as well as cue-, priming- and stress-induced reinstatement of nicotine-seeking behavior. These effects were accompanied by a decrease of the firing and burst rates in the ventral tegmental area dopamine neurons in response to nicotine. On the other hand, AM4113 pretreatment did not have effects on operant responding for food. Importantly, AM4113 did not have effects on anxiety and showed antidepressant-like effects.. Our results indicate that AM4113 could be a promising therapeutic option for the prevention of relapse to nicotine-seeking while lacking anxiety/depression-like side effects.

Topics: Animals; Anxiety; Behavior, Addictive; Behavior, Animal; Cannabinoid Receptor Antagonists; Cues; Depression; Disease Models, Animal; Dopaminergic Neurons; Dose-Response Relationship, Drug; Drug Inverse Agonism; Drug-Seeking Behavior; Male; Maze Learning; Mesencephalon; Motivation; Motor Activity; Piperidines; Pyrazoles; Rats, Long-Evans; Rats, Wistar; Receptor, Cannabinoid, CB1; Rimonabant; Signal Transduction; Swimming; Time Factors; Tobacco Use Cessation Devices; Tobacco Use Disorder; Weight Loss