Serotonin-enhancing drugs

Through its projections to various brain areas, serotonin participates to the control of numerous functions, like sleep, mood regulation, fear and anxiety, aggressiveness, motivation and reward, learning and memory, hunger, sexual activity, circadian rhythm regulation, neuroendocrine regulation, stress response and pain sensitivity. The multiplicity of the effects mediated by serotonin derives from the interaction of this neurotransmitter with a wide variety of membrane receptors localized in both the nervous system (central and peripheral) and peripheral organs. In fact, such receptors were localized also in the heart and other sites of the cardiovascular system, as well as in the gastrointestinal system. Recent genetic and molecular biology studies lead to the identification of at least 15 different serotonin receptor subtypes that ensure enormous variability in the response associated to the serotonergic system. However, despite the elevated number of receptors, serotonin receptor pharmacology is relatively recent, and few are the drugs currently marketed which act at a serotonin receptor level. Hence, the drugs which are better known as serotonergic system modulators are not the agonists or antagonists of the various serotonin receptor subtypes, but the serotonin transporter inhibitors. These are drugs that block neuronal serotonin reuptake, although with different potency and selectivity, and are effective in treating mood, depressive, anxiety, and eating disorders.