5-Hydroxytryptamine (5-HT) has both excitatory and inhibitory actions in the CNS and PNS. The development of new 5-HT ligands has led to the expansion of 5-HT receptor subtypes into three categories: 5-HT1, 5-HT2 and 5-HT3 (Ref. 1). Each category has further subdivisions. The literature concerning the biochemical basis of this division has been reviewed recently2. While this approach has elucidated many of the pharmacological properties of 5-HT receptors, it has not addressed the question of how 5-HT modulates cell excitability. Physiological studies have confirmed the existence of a multiplicity of 5-HT receptors that act through a variety of ionic mechanisms. The purpose of this review is to summarize what is known of the ionic mechanisms associated with the activation of identified mammalian 5-HT receptor subtypes, as well as some effects of 5-HT where the receptor could not be defined.
ASJC Scopus subject areas