Translator Disclaimer
1 November 2004 Mesenteric Arterial Relaxation to Calcitonin Gene-Related Peptide Is Increased During Pregnancy and by Sex Steroid Hormones
P. R. R. Gangula, P. Lanlua, R. D. Bukoski, S. J. Wimalawansa, C. Yallampalli
Author Affiliations +
Abstract

The present study investigated whether pregnancy and circulatory ovarian hormones increase the sensitivity of the mesenteric artery to calcitonin gene-related peptide (CGRP)-induced relaxation and possible mechanisms involved in this process. Mesenteric arteries from young adult male rats or female rats (during estrous cycle, after ovariectomy, at Day 20 of gestation, or Postpartum Day 2) were isolated, and the responsiveness of the vessels to CGRP was examined with a small vessel myograph. The CGRP (10−10 to 10−7 M) produced a concentration-dependent relaxation of norepinephrine-induced contractions in mesenteric arteries of all groups. Arterial relaxation sensitivity to CGRP was significantly (P < 0.05) greater in female rats compared with male rats. Pregnancy increased the sensitivity to CGRP significantly (P < 0.05) compared to ovariectomized and Postpartum Day 2 rats. In pregnant rats, CGRP-receptor antagonist, CGRP8–37, inhibited the relaxation responses produced by CGRP. The CGRP-induced relaxation was not affected by NG-nitro-l-arginine methyl ester (nitric oxide inhibitor, 10−4 M) but was significantly (P < 0.05) attenuated by an inhibitor of guanylate cyclase (1H-[1, 2, 4]oxadizaolo[4, 3-a]quinoxalin-1-one, 10−5 M). Relaxation responses of CGRP on mesenteric arteries were blocked (P < 0.05) by a cAMP-dependent protein kinase A inhibitor, Rp-cAMPs (10−5 M). The CGRP-induced vasorelaxation was significantly (P < 0.05) attenuated by calcium-dependent (tetraethylammonium, 10−3 M), but not ATP-sensitive (glybenclamide, 10−5 M), potassium channel blocker. Therefore, the results of the present study suggest that mesenteric vascular sensitivity to CGRP is higher during pregnancy and that cAMP, cGMP, and calcium-dependent potassium channels appear to be involved. Therefore, we propose that CGRP-mediated vasodilation may be important to maintain vascular adaptations during pregnancy.

P. R. R. Gangula, P. Lanlua, R. D. Bukoski, S. J. Wimalawansa, and C. Yallampalli "Mesenteric Arterial Relaxation to Calcitonin Gene-Related Peptide Is Increased During Pregnancy and by Sex Steroid Hormones," Biology of Reproduction 71(5), 1739-1745, (1 November 2004). https://doi.org/10.1095/biolreprod.104.031369
Received: 26 April 2004; Accepted: 1 July 2004; Published: 1 November 2004
JOURNAL ARTICLE
7 PAGES


Share
SHARE
KEYWORDS
pregnancy
steroid hormones
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top