Comparing the Molecular Pharmacology of CGRP and Adrenomedullin

CGRP and adrenomedullin [AM] are peptides that have a number of physiological effects, including vasodilation, through the activation of a shared GPCR, the family B calcitonin receptor-like receptor [CLR]. Specificity to each ligand is conferred through the unusual association of CLR with a single transmembrane accessory protein. For CGRP this is receptor activity-modifying protein 1 [RAMP1] and for AM acting at the AM1 receptor this is RAMP2. Receptor signalling by two specific peptide ligands through a common GPCR provides researchers with vital and unique information into similarities and differences of GPCR activation. Understanding the structure and function of these receptors will also provide a platform for future drug design for a number of cardiovascular and metabolic diseases in which CGRP and AM have been implicated. This review summarises the latest information and data concerning ligand binding, receptor activation and structural studies for both the CGRP and AM receptors.