Neurobiology of sexual function

S-HTia,2a,2c Serotonergic receptor subtypes ai-ADR Adrenergic receptor subtype D, 2 Dopaminergic receptor subtypes 

Understanding human sexual function and behavior and the various neurotransmitters and endocrine factors involved in the human sexual cycle is of paramount importance for proper diagnosis, understanding, and treatment of sexual dysfunction.1 Moreover, it is estimated that 20-85% of non-adherence to psychopharmacology is due to adverse sexual side-effects of the drugs. 

Stimulation of ai-adrenoreceptors will likely lead to detumescense, whereas blockade of these receptors, centrally and peripherally, including penile tissue, may produce erection. Female sexual arousal has been associated with an active sympathetic nervous system, but the overall data concerning the role of various neurotransmitters in female sexual function are still scanty. 

Most prominent among the psychotropics that enhance serotonergic transmission are the selective serotonin reuptake inhibitors (SSRIs), which may induce sexual dysfunction in as many as 50-75% of patients, in part by activation of central 5-HT2 receptors. Antidepressants that antagonize the 5-HT2 receptor, such as mirtazapine and trazodone, cause fewer sexual side-effects compared with the SSRIs. Stimulation of the 5-HTia receptor facilitates sexual functioning, while activation of the 5-HTib,id and 5-HTic receptors inhibits 

Other neurotransmitter systems, as well as various hormones, have been shown to modulate sexual function among these are progesterone and prolactin (which inhibit centrally mediated arousal) and testosterone (which stimulates centrally mediated arousal). 

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Meston CM, Frohlich PF. The neurobiology of sexual function. Arch Gen Psychiatry 2000 57 1012-1030. 

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