M. Oike et al., ANGIOTENSIN-II ATTENUATES VASCULAR CONTRACTILITY IN THE RABBIT MESENTERIC-ARTERY, Biochemical and biophysical research communications, 222(2), 1996, pp. 208-214
We observed the effects of angiotensin II (AII) on the contractile res
ponse and the Ca2+ transient induced by high K+ solution in the rabbit
mesenteric artery. In the control condition, the repeated application
of high K+ solution with 90 min interval induced a gradually increasi
ng contraction, which was accompanied with a significant elevation of
the intracellular calcium concentration ([Ca2+](i)). Treatment of the
tissue with AII for one to two hours abolished the incremental respons
e of the contraction. The change in [Ca2+](i) induced by high K+ solut
ion, however, was not significantly different with and without treatme
nt with AII. Pretreatment of the tissue with actinomycin D abolished t
he inhibitory action of AII on the incremental contraction, indicating
the involvement of a transcriptional process. These results indicate
that AII impairs vascular contractility through the modulation of Ca2-sensitivity of the contractile machinery. (C) 1996 Academic Press, In
c.