Role of omega-conotoxin GVIA-sensitive Ca2+ entry in angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding in bovine adrenal medullary cells.
The relative contributions of Ca2+ influx and intracellular Ca2+ mobilization were examined for angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding, which reflects the level of activated protein kinase C in bovine chromaffin cells. Angiotensin II receptors activate phospholipase C in chromaffin cells, leading to a short-lived mobilization of intracellular Ca2+. Angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding was largely blocked in Ca(2+)-free buffer and by pretreatment with the Ca(2+)-channel blocker omega-conotoxin GVIA. The [3H]phorbol 12,13-dibutyrate binding response to [Sar1]angiotensin II also appeared to be voltage sensitive, as no additivity was observed with the response to the depolarizing agent 4-aminopyridine (3 mM). Threshold sensitivities of the extra- and intracellular Ca(2+)-mobilizing pathways to angiotensin II were similar, and all examined effects of angiotensin II in these cells were apparently mediated by losartan-sensitive (AT1-like) receptors. The dependence of angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding on extracellular Ca2+ entry, in contrast to stimulation by other phospholipase C-linked receptor agonists (bradykinin and methacholine), suggests that angiotensin II preferentially stimulates protein kinase C translocation to the plasma membrane, rather than to internal membranes, in bovine adrenal medullary cells.
Laboratory of Molecular and Integrative Neuroscience, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, North Carolina 27709.
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McMillian
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PM
Hudson
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Suh
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Ye
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RK
Tuominen
J S
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Hong
D000313:Adrenal Medulla / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004056:Differential Threshold; D008564:Membrane Potentials; D009994:Osmolar Concentration; D010456:Peptides, Cyclic / Q000494:pharmacology*; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism*; D014316:Tritium; D020866:omega-Conotoxin GVIA
D010456:Peptides, Cyclic; D014316:Tritium; D000804:Angiotensin II; D015240:Phorbol 12,13-Dibutyrate; C074793:angiotensin II, Sar(1)-; D020866:omega-Conotoxin GVIA; D002118:Calcium