혈관 평활근에 대한 안지온텐신 II의 작용기전
Action of angiotensin II on the vascular smooth muscle in isolated rabbit aorta

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서울대학교 의과대학
Seoul J Med 1980;21(3):281-290
The activation mechanism of vascular smooth muscle
by angiotensin 11 (A. 11) was studied in isolated
aorta. Helical strips of arterial muscle were prepared
from the descending thoracic aorta of rabbit. All
experiments were performed in HCO-a-buffered Tyrode
solution which was aerated with 3% CO,-97%
0, mixed gas and kept at 35°C. In the experiment
for the effect of La' on the A. II-induced contraction,
however, tris-buffered Tyrode solution aerated wih
100% 0, was used.
Contractile response appeared from the concentration
of 10-'M A. II, and reached a maximum level at
10-1M A. II. The amplitude of contraction was not altered, if helical strips were exposed repeatedly to
A. II for 6 minutes every 30 minutes, showing that
there was no tachyphylaxis for the action of angiotensin
A. II produced a contraction even on the contracture
induced by K-depolarization, and also in K·
Tyrode solution pretreated with verapamil or La",
In Call-free Tyrode solution, A. II induced a contraction,
but the contraction was not sustained and
decreased gradually. The amplitude of A. n·induced
contraction was dependent on external bathing Call:
The contraction increased dose-dependently, up to 2
mM Ca", but above that the amplitude was decreasing.
The sustained contraction induced by 1O-8M A. II
was suppressed significantly by the addition of «-blocker.
The results of this experiment suggest that A. IIinduced
contraetion was developed by its direct action
on the smooth muscle and also the indirect
action mediated through the adrenergic endings, and
that A. II action is independent of changes in transmembrane
potential and associated with promoting
both transmembrane Ca*-influx and the mobilization
of cellular Ca",
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College of Medicine/School of Medicine (의과대학/대학원)Dept. of Medicine (의학과)The Seoul Journal of MedicineThe Seoul Journal of Medicine Vol. 21 No.3 (1980)
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