T-type calcium channels in adrenal glomerulosa cells: GTP-dependent modulation by angiotensin II.
With the use of whole-cell and single-channel current recordings, we have examined in more detail the site of action of angiotensin II (AII) on multiple populations of voltage-gated calcium channels in bovine adrenal glomerulosa cells. AII (10 nM) enhances whole-cell T-type calcium channel current and increases the activity of single T-type calcium channels in cell-attached patch recordings. The AII-induced enhancement of whole-cell calcium channel currents is dependent on the presence of internal GTP and can be inhibited by the competitive AII-receptor antagonist saralasin (1 microM). These results show that AII augments the T-type calcium channel current in bovine adrenal glomerulosa cells.
McCarthy
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RT
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.
Isales
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Rasmussen
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D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D004594:Electrophysiology / Q000379:methods; D019204:GTP-Binding Proteins / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D012504:Saralasin / Q000494:pharmacology; D015290:Second Messenger Systems / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology; D015384:Zona Glomerulosa / Q000187:drug effects / Q000502:physiology*
D015220:Calcium Channels; D000804:Angiotensin II; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D013779:Tetrodotoxin; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D012504:Saralasin