Serotonin and anaesthesia

Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter(Fig. 1) synthesized in serotonergic neurones in the centralnervous system (CNS), enterochromaffin cells in the gastrointestinaltract, and platelets. 5-HT is involved in a number of physiological systems of relevanceto the anaesthetist, including vascular reactivity, bronchomotortone, platelet aggregation, pain modulation, and nausea andvomiting. The exact sites and modes of action of 5-HT remainill-defined and elusive. Many patients presenting for anaesthesia are taking medicationswith 5-HT agonist or antagonist activity. There is the potentialfor interaction with drugs administered in the perioperativeperiod that modulate 5-HT activity. Toxic effects of excessiveCNS 5-HT concentrations can precipitate intensive care unit(ICU) admission.