Phosphoinositide hydrolysis and calcium mobilization induced by vasopressin and angiotensin II in cultured vascular smooth muscle cells.
The cellular action of vasoconstrictive hormones, angiotensin II (AII) and Arg8-vasopressin (AVP), on vascular smooth muscle (VSM) in cultured VSM cells from rat mesenteric artery was studied. Both AII and AVP specifically induce a transient increases in cytosolic free calcium independent of extracellular calcium or calcium channels activated by high potassium depolarization in VSM cells loaded with Fura-2. Vasoconstrictive hormones induce a dose-dependency with formation of inositolphosphates. Analysis using high pressure liquid chromatography has shown that AVP stimulates rapid and transient increases in inositol 1,3,4-trisphosphate, inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate within 1 minute. Moreover, a laser-excitation fluorescence system reveals high calcium concentration sites in subsarcolemmal region. These results indicate that, unlike voltage-dependent calcium influx across the cell membrane, AII and AVP induce receptor-mediated increases in cytosolic free calcium via phosphoinositide hydrolysis creating an intracellular messenger for calcium release from intracellular calcium stores.
Takeuchi
K
K
Second Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Abe
K
K
Yasujima
M
M
Sato
M
M
Maeyama
K
K
Watanabe
T
T
Sato
S
S
Inaba
H
H
Yoshinaga
K
K
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000378:metabolism; D016257:Fura-2; D006868:Hydrolysis; D007834:Lasers; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D010716:Phosphatidylinositols; D000804:Angiotensin II; D001127:Arginine Vasopressin; D011188:Potassium; D002118:Calcium; D016257:Fura-2