Stimulatory effect of angiotensin II on calcium efflux from cultured bovine adrenal chromaffin cells.
The effect of angiotensin II on Ca2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Angiotensin II (10(-7)M) increased the intracellular free Ca2+ level ([Ca2+]i) to a peak in the presence or absence of extracellular Ca2+, followed by decrease with time. Angiotensin II (10(-9)-10(-6)M) also stimulated 45Ca2+ efflux from cultured bovine adrenal chromaffin cells in a concentration-dependent manner. Its stimulatory effect on 45Ca2+ efflux was inhibited by the angiotensin II antagonist [Sar1, Ile8]-angiotensin II or [Sar1, Val5, Ala8]-angiotensin II. The increase in angiotensin II-stimulated 45Ca2+ efflux was dependent on the extracellular Na+ concentration. Angiotensin II also increased 22Na+ influx into the cells. These results indicate that stimulation of the angiotensin II receptor induces extracellular Na(+)-dependent Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably by acceleration of Na+/Ca2+ exchange.
Houchi
H
H
Department of Pharmacology, School of Medicine, Tokushima, Japan.
Okuno
M
M
Kitamura
K
K
Ishimura
Y
Y
Ohuchi
T
T
Tokumura
A
A
Oka
M
M
D000313:Adrenal Medulla / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012979:Sodium Radioisotopes; D019831:Sodium-Calcium Exchanger; D013268:Stimulation, Chemical
D002132:Calcium Radioisotopes; D002352:Carrier Proteins; D012979:Sodium Radioisotopes; D019831:Sodium-Calcium Exchanger; D000804:Angiotensin II; D012964:Sodium; D002118:Calcium