Co-existence of neuropeptides and differential inhibition of vasodilator responses by neuropeptide Y in guinea pig uterine arteries.
The co-localization of substance P (SP) with calcitonin gene-related peptide (CGRP), and vasoactive intestinal peptide (VIP) with neuropeptide Y (NPY) of the guinea pig uterine artery were investigated with immunocytochemistry. The SP/CGRP fibre population was distinct from the VIP/NPY fibre population. Both types of fibres ran in the medial-adventitial border, and appeared as coarsed and fine varicosed. Uterine arterial dilatation was evoked by acetylcholine (ACh), SP, CGRP, and VIP in precontracted arteries as examined by a sensitive in vitro method. Strong relaxations were seen by ACh, CGRP and VIP. NPY had no relaxant effect per se but was found to be a potent inhibitor of vasodilation induced by ACh and SP, while relaxations induced by VIP and CGRP were unaffected. The functional significance of NPY in the uterine artery may to a large extent be to increase tension not only by potentiation of contraction but additionally by inhibiting vasodilator responses.
Fallgren
B
B
Department of Zoophysiology, University of Lund, Sweden.
Ekblad
E
E
Edvinsson
L
L
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000294:innervation*; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006168:Guinea Pigs; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009478:Neuropeptide Y / Q000378:metabolism* / Q000494:pharmacology; D009479:Neuropeptides / Q000378:metabolism* / Q000494:pharmacology; D013373:Substance P / Q000378:metabolism* / Q000494:pharmacology; D014599:Uterus / Q000098:blood supply* / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
D009478:Neuropeptide Y; D009479:Neuropeptides; D014665:Vasodilator Agents; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D015740:Calcitonin Gene-Related Peptide