Mechanism of vasodilation by cochlear nerve stimulation. Role of calcitonin gene-related peptide.
Rabbit aortic rings pre-contracted with 1 microm phenylephrine were exposed to organ fluid of isolated guinea pig cochleas which had been subjected to electrical field stimulation (FS, 50 Hz, 50 V, 0.2 ms over 2 min). This resulted in an endothelium-dependent relaxation of the vessel rings sensitive to glibenclamide, an ATP-sensitive K+channel blocker. Tetrodotoxin (1 microm) added to the cochlear fluid blocked the vasorelaxant effect of cochlear FS and it attenuated vasorelaxation when added to aortic rings. The relaxation response paralleled an increase in the level of calcitonin gene-related peptide (CGRP) in both cochlear and vascular organ fluids from undetectable pre-stimulation values to 0.12+/-0.029 and 0.44+/-0.051 n m, respectively. We conclude that CGRP possibly contributes to cochlear nerve stimulation-induced endothelium-dependent vasorelaxation.
Szilvassy
J
J
Department of Oto-Rhino-Laryngology, Albert Szent-Györgyi Medical University, Szeged, Tisza Lajos krt. 111, H-6720, Hungary.
Jancso
G
G
Ferdinandy
P
P
D000818:Animals; D001011:Aorta; D015740:Calcitonin Gene-Related Peptide / Q000502:physiology*; D003056:Cochlear Nerve / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D015221:Potassium Channels / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*
D015221:Potassium Channels; D015740:Calcitonin Gene-Related Peptide