Calcitonin gene-related peptide (CGRP), a 37 amino acid neuropeptide, identified in multiple species, has widespread distribution and expression. CGRP acts through G protein-coupled receptors whose presence and changes in function modulate the peptide′s effects in various tissues. Three receptor subtypes have been identified and CGRP′s signal transduction through the receptors is dependent on two accessory proteins: Receptor activity modifying protein1 (RAMP1) and Receptor component protein (RCP). Several endogenous substances such as glucocorticoids, nitric oxide (NO), nerve growth factors (NGF), and steroid hormones modulate CGRP release and synthesis. Both peptide and non-peptide agonists and antagonists of CGRP receptors are being developed. Also the therapeutic benefits of some antagonists such as BIBN 4096 BS in migraine have been promising. This brief review provides a preliminary understanding of the diverse biological effects of the peptide in various systems. The current status of CGRP and its receptors in many pathophysiological states is not fully explored and future findings are greatly awaited
