Cyclosporin A augments angiotensin II-stimulated rise in intracellular free calcium in vascular smooth muscle cells.
Pretreatment of rat vascular smooth muscle cells with the immunosuppressive drug cyclosporin A caused concentration- and time-dependent increases in both the amplitude and duration of the angiotensin II-induced rise in cytosolic free calcium, as measured with quin 2. Cyclosporin A had no significant effect on basal quin 2 fluorescence. However, cyclosporin A increased the basal 45Ca2+ influx. This stimulation of 45Ca2+ influx was not blocked by nifedipine (10(-6) M). Cyclosporin A also augmented the angiotensin II-stimulated influx and efflux of 45Ca2+. These results demonstrate that cyclosporin A increases the permeability of the plasma membrane for Ca2+ and also augments the angiotensin II-induced increases in cytosolic free calcium.
Pfeilschifter
J
J
Physiologisches Institut der Universität Zürich, Switzerland.
Rüegg
U T
UT
D000804:Angiotensin II / Q000493:pharmacokinetics*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D003524:Cyclosporins / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D013268:Stimulation, Chemical
D003524:Cyclosporins; D000804:Angiotensin II; D002118:Calcium