seen in many psychopathological conditions. Stimulation of 5-HT2C receptors leads to increase of corticotropin releasing hormone (CRH) and vasopressin mRNA in the paraventricular nucleus and proopiomelanocortin in the anterior pituitary lobe. In rats, restraint stress (which can produce depressive symptoms if being chronic) induces secretion of prolactin, ACTH, vasopressin and oxytocin which is partially mediated via 5-HT2C receptor. Responses during such conditions as dehydration or haemorrhage causes the release oxytocin via serotonergic response that is partly mediated via 5-HT2C. In addition, peripheral release of vasopressin involves serotonergic response which is partially mediated via 5-HT2C. Expression of the 5-HT2C receptor in the CNS is modulated by female sex hormones estradiol and progesterone. Combination of the hormones decrease the receptor concentration in the ventral hippocampus in rats and could thus affect mood. Genetics Many human polymorphisms have been identified influencing the expression of 5-HT2C. Significant correlations are suggested, specifically in relation to psychiatric disorders such as depression, OCD, and anxiety-related conditions. Polymorphisms also correlate with susceptibility to a number of conditions including substance use disorders and obesity. There are indications that the alternative splicing of the 5-HT2C receptor is regulated by a snoRNA called SNORD115, the deletion of which is associated with Prader–Willi syndrome. As the human gene is located in the X chromosome, males have only one copy of the gene whereas women have two, meaning that mutations in the gene affect the phenotype of men even when the allele would be recessive in nature. As women have two copies of the gene, but only one allele is expressed in each cell, they are a mosaic for polymorphisms, meaning that one genetic variant may be prevalent in one tissue and another variant will be prevalent in a different tissue (as with all other x-linked genetic variations). Ligands Agonists A-372,159 AL-38022A CP-809,101 CPD-1 Fenfluramine Lisuride Lorcaserin Mesulergine MK-212 Naphthylisopropylamine Norfenfluramine Org 12,962 ORG-37,684 Oxaflozane PF-04479745 PNU-22394 PNU-181731 Psychedelics Lysergamides (LSD, etc.) Phenethylamines (2C-B, DOI, DOM, Mescaline, etc.) Piperazines (mCPP, TFMPP, etc.) Tryptamines (5-MeO-DMT, Bufotenin, DMT, Psilocin, etc.) Ro60-0175 Vabicaserin WAY-629 WAY-161,503 WAY-163,909 YM-348 CP-132,484 also 5HT2a agonist. Partial agonists Aripiprazole Antagonists Agomelatine CEPC Eltoprazine Etoperidone Flibanserin Fluoxetine FR-260,010 Tedatioxetine Methysergide Mirtazapine Nefazodone Norfluoxetine O-Desmethyltramadol Promethazine RS-102,221 SB-200,646 SB-221,284 SB-228,357 SB-242,084 SDZ SER-082 Tramadol Trazodone Inverse agonists Antidepressants Tricyclics (Amitriptyline and Nortriptyline most notably) Tetracyclics (Mirtazapine, Mianserin, Amoxapine, etc.) Antihistamines (Cyproheptadine, Hydroxyzine, Latrepirdine, etc.) Antipsychotics Typicals (Chlorpromazine, Fluphenazine, Loxapine, Thioridazine, etc.) Atypicals (Clozapine,