Neurogenic vasodilation and release of calcitonin gene-related peptide (CGRP) from perivascular nerves in the rat mesenteric artery.
The effect of perivascular nerve stimulation (PNS) on the release of calcitonin gene-related peptide (CGRP) was examined by radioimmunoassay (RIA) in isolated, perfused rat mesenteric arteries. The released CGRP-like immunoreactivity (CGRP-LI) was identified to be CGRP itself and its oxidized form by combined analysis with RIA and high performance liquid chromatography. CGRP-LI was localized in the perivascular nerves of the large mesenteric artery and its branches. In the preparation precontracted by methoxamine, and perfused with a solution containing guanethidine, an adrenergic neuron blocker, PNS induced vasodilator responses and an increase of CGRP-LI in the perfusate in a frequency-dependent manner. Both the responses were attenuated by tetrodotoxin (10(-6) M), suggesting that they were neurogenic in origin. Removal of Ca2+ from the perfusing solution also abolished the PNS-induced release of CGRP-LI. These findings suggest that CGRP plays a transmitter role in the neurogenic vasodilation in the rat mesenteric vascular bed.
Fujimori
A
A
Department of Pharmacology, University of Tsukuba, Ibaraki, Japan.
Saito
A
A
Kimura
S
S
Watanabe
T
T
Uchiyama
Y
Y
Kawasaki
H
H
Goto
K
K
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002118:Calcium / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D004558:Electric Stimulation; D008297:Male; D008638:Mesenteric Arteries / Q000294:innervation* / Q000502:physiology; D009412:Nerve Fibers / Q000502:physiology; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology; D014664:Vasodilation / Q000502:physiology*
D013779:Tetrodotoxin; D015740:Calcitonin Gene-Related Peptide; D002118:Calcium