5-HYDROXYTRYPTAMINE RECEPTORS

5‐Hydroxytryptamine (5‐HT) receptors consist of at least three distinct types of molecular structures (Table 1): guanine nucleotide binding protein (G protein)‐coupled receptors, ligand‐gated ion channels, and transporters. Prior to the introduction of molecular biological techniques, the classification of 5‐HT receptors was based predominantly on the pharmacological properties of the receptors. For example, “5‐HT1” receptors were defined as membrane binding sites that displayed nanomolar affinity for [3H]5‐HT (Peroutka and Snyder, 1979). Subsequently, Bradley et al. (1986) defined “5‐HT1‐like” receptors by their susceptibility to antagonism by methiothepin and/or methysergide, resistance to antagonism by 5‐HT2 antagonists, and potent agonism by 5‐carboxamidotryptamine (5‐CT). Thus, these classification systems are dependent upon the availability of selective pharmacological agents. Copyright © 1993, Wiley Blackwell. All rights reserved