INFLUENCE OF CALCITONIN-GENE-RELATED PEPTIDE ON COCHLEAR BLOOD-FLOW AND ELECTROPHYSIOLOGY

Intra-arterially infused calcitonin gene-related peptide (CGRP) induce d dose-dependent decreases in both systemic blood pressure and cochlea r blood flow (CBF). However, when subjects were pretreated systemicall y or locally with the specific receptor antagonist CGRP(8-37), CBF inc reased, despite decreases in systemic blood pressure in response to CG RP infusions. Micro-infusions of CGRP directly into the supplying arte rial network of the cochlea induced dose-dependent increases in CBF th at were blocked by CGRP(8-37) pretreatment. Cochlear electrophysiology , as assessed by cochlear action potential and cochlear microphonics, remained unchanged following each condition tested. These results indi cate that CGRP is involved in systemic regulation of blood pressure an d contributes to the regulation of CBF.