MELATONIN RECEPTORS - ARE THERE MULTIPLE SUBTYPES

There is now evidence for more than one site of action for the hormone melatonin (N-acetyl-5-methoxytryptamine). Recent pharmacological and molecular advances are providing the tools to address the characteriza tion of melatonin receptor subtypes. The development of novel melatoni n receptor agonists and antagonists, high-affinity radioligands, quant itative bioassays, and the recent cloning of melatonin receptors are f urthering our understanding of native and recombinant melatonin recept ors. In this article, Margarita Dubocovich discusses the properties of melatonin receptors, and the basis for their classification into at l east two subtypes, the ML(1) and ML(2).