title: The serotonin 5-HT2Creceptor and the non-addictive nature of classic hallucinogens.
abstract: Classic hallucinogens share pharmacology as serotonin 5-HT2A, 5-HT2B, and 5-HT2Creceptor agonists. Unique among most other Schedule 1 drugs, they are generally non-addictive and can be effective tools in the treatment of addiction. Mechanisms underlying these attributes are largely unknown. However, many preclinical studies show that 5-HT2Cagonists counteract the addictive effects of drugs from several classes, suggesting this pharmacological property of classic hallucinogens may be significant. Drawing from a comprehensive analysis of preclinical behavior, neuroanatomy, and neurochemistry studies, this review builds rationale for this hypothesis, and also proposes a testable, neurobiological framework. 5-HT2Cagonists work, in part, by modulating dopamine neuron activity in the ventral tegmental area-nucleus accumbens (NAc) reward pathway. We argue that activation of 5-HT2Creceptors on NAc shell, GABAergic, medium spiny neurons inhibits potassium Kv1.x channels, thereby enhancing inhibitory activity via intrinsic mechanisms. Together with experiments that show that addictive drugs, such as cocaine, potentiate Kv1.x channels, thereby suppressing NAc shell GABAergic activity, this hypothesis provides a mechanism by which classic hallucinogen-mediated stimulation of 5-HT2Creceptors could thwart addiction. It also provides a potential reason for the non-addictive nature of classic hallucinogens.
authors.affiliation: 1 Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, USA.
authors.forename: Clinton E
authors.initials: CE
authors.lastname: Canal
authors.affiliation: 2 Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, USA.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Murnane
mesh_terms: D000818:Animals; D016739:Behavior, Addictive / Q000378:metabolism; D003042:Cocaine / Q000494:pharmacology; D006213:Hallucinogens / Q000494:pharmacology*; D006801:Humans; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism*; D044405:Receptor, Serotonin, 5-HT2C / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D058826:Serotonin 5-HT2 Receptor Agonists / Q000494:pharmacology; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000378:metabolism
chemical_list: D006213:Hallucinogens; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D058826:Serotonin 5-HT2 Receptor Agonists; D012701:Serotonin; D003042:Cocaine
keywords: 5-HT2C; Hallucinogens; Kv1; addiction; cocaine