α1‐Adrenoceptor subtypes in the mouse mesenteric artery and abdominal aorta

Publisher Website
Google Scholar
Abstract
Subtypes of α1‐adrenoceptor‐mediated contractions to noradrenaline in mouse mesenteric artery and abdominal aorta were examined. In mesenteric artery, BMY7378, 5‐methylurapidil, WB4101 and prazosin were inhibited contraction to noradrenaline The good correlation for pA2 values of antagonists in native α1D‐ (rat thoracic aorta) adrenoceptor subtype and pKi values in rat cloned α1d‐adrenoceptor with the pA2 values estimated in the mouse mesenteric artery was obtained. However, the pA2 value for BMY7378 is significantly lower than the accepted value against the α1D‐adrenoceptor subtype. In the abdominal aorta, it was obtained the regional difference for the sensitivity for noradrenaline. In the upper abdominal aorta, the good correlation for the pA2 values of the antagonists in the native α1D‐adrenoceptor subtype and pKi values in the cloned α1d‐adrenoceptor with the pA2 values estimated in the upper abdominal aorta was obtained, and regression line was close to the line of identity. In the lower abdominal aorta, the good correlation for the reported pKi values in the cloned α1a‐adrenoceptor subtype with the pA2 values estimated in the mouse lower abdominal aorta was obtained, and regression line was close to the line of identity. In conclusion, the present functional data in the mouse suggest that (1) α1D‐like adrenoceptors are present in the mesenteric artery, (2) there is the regional difference for the sensitivity for noradrenaline in the abdominal aorta and (3) noradrenaline evokes the contraction mediated through α1D‐adrenoceptor in the upper abdominal aorta, whereas there is α1A‐adrenoceptor‐mediated contraction in the lower abdominal aorta. British Journal of Pharmacology (2001) 134, 1045–1054; doi:10.1038/sj.bjp.0704350