Vasorelaxant response to isoprenaline, nitric oxide donor, calcitonin gene-related peptide and vasoactive intestinal peptide in aortic rings of adult C57BL/6J mice

The mouse and tissues from this species are increasingly used as experimental models because of the wide variety of gene deletions and overexpressions available in this species. Yet, very little is known about normal vascular responses in the mouse. We investigated the vasorelaxant responses on thoracic aortic rings from the adult male C57BL/6J mouse. Isoprenaline, acetylcholine, calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and sodium nitroprusside all caused concentration-dependent relaxations in aortic rings possessing healthy endothelium and precontracted with phenylephrine. Maximum relaxations were 64.9 +/- 2.6%, 66.8 +/- 2.9%, 114.3 +/- 4.6%, 65.1 +/- 4.2% and 116.2 +/- 5.1% with -logEC(50) values of 6.76 +/- 0.14, 7.04 +/- 0.11, 8.53 +/- 0.14, 8.29 +/- 0.26 and 8.10 +/- 0.20 for isoprenaline, acetylcholine, CGRP, VIP and sodium nitroprusside, respectively. There were significantly smaller responses to isoprenaline, acetylcholine, CGRP and VIP when the endothelium was denuded. The maximum relaxations for isoprenaline, CGRP and acetylcholine were 48.3 +/- 5.1%, 99.6 +/- 4.4% and 5.7 +/- 1.6% with -logEC(50) values of 6.44 +/- 0.40 and 8.23 +/- 0.192, respectively, following endothelium removal. The response to VIP was completely dependent to endothelium. Without precontraction, isoprenaline, at the higher doses, caused small contractions. These experiments provide new information about vascular responses of five vasodilators in aortic rings of adult male C57BL/6J mice. (C) 2001 Published by Elsevier Science B.V.