Vasopressor peptides and depolarization stimulated Ca2+-entry into cultured vascular smooth muscle.
45Ca-uptake was measured in monolayers of cultured rat aortic smooth muscle cells. Sufficient extracellular 45Ca could be removed by a 90 second cold La3+ was to reveal stimulation of 45Ca-uptake by high K+-depolarization and the vasopressor peptides angiotensin II and vasopressin. The high K+-stimulated 45Ca-influx was blocked by a dihydropyridine-type Ca2+-antagonist while that stimulated by angiotensin II or vasopressin was not. The 45Ca-influx stimulated by high K+-depolarization was additive to that stimulated by angiotensin II. Vasopressin and angiotensin II stimulated 45Ca-fluxes were not additive. It is concluded that vasopressor peptides stimulate Ca2+-entry through receptor operated Ca2+-channels which are distinct from voltage gated Ca2+-channels.
Zschauer
A
A
Department of Research, University Hospital, Basel, Switzerland.
Scott-Burden
T
T
Bühler
F R
FR
van Breemen
C
C
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004553:Electric Conductivity; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D014667:Vasopressins / Q000494:pharmacology*
D014667:Vasopressins; D000804:Angiotensin II; D011188:Potassium; D002118:Calcium