Vasorelaxant response to isoprenaline, nitric oxide donor, calcitonin gene-related peptide and vasoactive intestinal peptide in aortic rings of adultC57BL/6J mice

The mouse and tissues from this species are increasingly used as experiment al 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 thor acic aortic rings from the adult male C57BL/6J mouse. Isoprenaline, acetylc holine, calcitonin gene-related peptide (CGRP), vasoactive intestinal pepti de (VIP) and sodium nitroprusside all caused concentration-dependent relaxa tions 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 fo r isoprenaline, acetylcholine, CGRP, VIP and sodium nitroprusside, respecti vely. There were significantly smaller responses to isoprenaline, acetylcho line, CGRP and VIP when the endothelium was denuded. The maximum relaxation s 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 +/- 0.1 92, respectively, following endothelium removal. The response to VIP was co mpletely 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.