Calcitonin gene-related peptide: an endogenous mediator of preconditioning.

Preconditioning of the heart induced by a brief ischemia or hyperthermia is exerted in two phases, early and delayed protection. The cardioprotection of ischemic preconditioning is related to the release of endogenous mediators. Calcitonin gene-related peptide (CGRP), a principal transmitter of capsaicin-sensitive sensory nerves, is involved in the mediation of ischemic preconditioning, and CGRP-mediated ischemic preconditioning has been shown to protect the endothelial cells. The cardioprotection mediated by endogenous CGRP is also found in heat stress reaction. Drug-induced preconditioning, such as by nitroglycerin, may be related to stimulated release of CGRP. These findings suggest that CGRP may be an endogenous myocardial protective substance and plays an important role in the mediation of preconditioning.