Neuropeptide Y and mesenteric sympathetic vasoconstriction in pregnant and non-pregnant Wistar-Kyoto rats.
1. We have investigated the role of neuropeptide Y (NPY) in sympathetic vasoconstriction and its possible contribution to decreased mesenteric vasoconstrictor responses to electrical field stimulation (EFS) in pregnancy in vivo using an in situ bloodperfused mesenteric preparation in 18-20 day pregnant and age-matched non-pregnant Wistar-Kyoto (WKY) rats. 2. Mean blood pressure (BP) was decreased in pregnant compared with non-pregnant rats. Mesenteric basal perfusion pressure (PP) was not significantly reduced in pregnancy. BIBP 3226, a specific NPY Y1 receptor antagonist, did not affect mean BP or mesenteric basal PP in pregnant or non-pregnant animals. 3. Mesenteric vasoconstrictor responses to EFS were blunted in pregnant compared with non-pregnant controls. BIBP 3226 significantly suppressed mesenteric vasoconstrictor responses to EFS in both pregnant and non-pregnant animals. Decreased mesenteric responses to EFS in pregnancy were still evident following NPY Y1 receptor blockade. 4. These results suggest that endogenous NPY plays a role in rat mesenteric sympathetic vasoconstriction in vivo. However, NPY is unlikely to be responsible for the impairment of EFS-induced mesenteric vasoconstriction in pregnant WKY rats.
University of Western Australia, Department of Medicine and West Australian Hearth Research Institute, Perth, Western Australia, Australia.
Z M
ZM
Chu
L J
LJ
Beilin
D000818:Animals; D019540:Area Under Curve; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000502:physiology; D004558:Electric Stimulation; D005260:Female; D009478:Neuropeptide Y / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D051381:Rats; D011921:Rats, Inbred WKY; D017476:Receptors, Neuropeptide Y / Q000037:antagonists & inhibitors; D013152:Splanchnic Circulation / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology*
C092926:BIBP 3226; D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y; D001120:Arginine