Novel discriminatory ligands for 5-HT2B receptors.

The 5-HT2B receptor is the most recent addition to the 5-HT2 receptor family and shares strong operational similarities with the structurally related 5-HT2A and 5-HT2C receptor subtypes. The strength of the pharmacological association, particularly between 5-HT2B and 5-HT2C receptors, suggests a need to consider carefully the use of ligands which may now be regarded as somewhat non-selective for the receptors in this class. The possibility that biological activity previously supposed to involve 5-HT2C receptors may actually involve 5-HT2B receptors highlights a need to develop ligands with improved selectivity profiles. In this regard, medicinal chemistry continues to provide novel ligands which, if truly selective, should facilitate our understanding of the physiology, pathophysiology and therapeutic potential of 5-HT2B receptor modulation. This article reviews some of the newest ligands which may be used in the discrimination and characterisation of 5-HT2B receptor function.