Calcitonin peptide bound to its receptor, illustration. The calcitonin gene-related peptide (CGRP, yellow) binds to its receptor (blue) on the membranes of neurons and smooth muscle cells in cerebral (brain) blood vessels. This activates a signal cascade through G-proteins (glowing blue, lower centre) that leads to a dilatation of brain blood vessels (vasodilatation). This is a factor in disorders such as migraines, and blocking this receptor is a potential treatment for migraines.