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.
McMillian
M K
MK
Laboratory of Molecular and Integrative Neuroscience, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, North Carolina 27709.
Hudson
P M
PM
Suh
H H
HH
Ye
H
H
Tuominen
R K
RK
Hong
J S
JS
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