Response of intracellular Ca2+ transients in cultured vascular smooth muscle cells to angiotensin II, vasopressin, acetylcholine and atrionatriuretic peptide.
Modulation of intracellular Ca2+ concentration [( Ca2+]i) is a signal for the contraction of vascular smooth muscle cells responding to vasoreactive substances. We prepared confluently cultured smooth muscle cells from rat aorta, loaded them with Ca2+ sensitive fluorescent dye, fura-2, and measured the [Ca2+]i transient by microscopic spectrofluorometry. The [Ca2+]i was distributed heterogeneously in cytosol. Angiotensin II (10 nM) transiently doubled the [Ca2+]i. It was also increased by arginine-vasopressin (10 nM), even after stimulation by angiotensin II was saturated. In contrast, acetylcholine (10 microM) or rat atrionatriuretic peptide (10 nM) did not change the [Ca2+]i in the same detecting field of the same cell, contradicting previous reports.
Shin
W S
WS
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Toyo-oka
T
T
Naitoh
T
T
Dan
Y
Y
Okai
Y
Y
Iizuka
M
M
Sugimoto
T
T
D000109:Acetylcholine / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D005470:Fluorometry; D016257:Fura-2; D007425:Intracellular Membranes / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013053:Spectrophotometry; D013268:Stimulation, Chemical
D001572:Benzofurans; D000804:Angiotensin II; D001127:Arginine Vasopressin; D009320:Atrial Natriuretic Factor; D000109:Acetylcholine; D002118:Calcium; D016257:Fura-2