Calcitonin gene-related peptide (CGRP) is a 37 amino acid peptide which belongs to a family of related peptidesincluding calcitonin, amylin, and adrenomedullin. It exists in two isoforms α-CGRP (or CGRP I) and β-CGRP(or CGRP II) which are very similar in their biological activities and are encoded by different genes. CGRP peptides are mainly localized in sensory and central neurons and have been implicated in a variety of physiological processes such as cardiovascular homeostasis, calcium metabolism, and control of fetoplacental vascular tone. Receptors for this family of peptides belong to the seven transmembrane G-protein-coupled receptors linked to theactivation of adenylate cyclase. Their interaction with receptor activity modifying proteins (RAMPs) is essential formembrane trafficking and for conferring ligand specificity.