Premium
Role of ω‐Conotoxin GVIA‐Sensitive Ca 2+ Entry in Angiotensin II‐Stimulated [ 3 H]Phorbol 12, 13‐Dibutyrate Binding in Bovine Adrenal Medullary Cells
Author(s) -
McMillian Michael K.,
Hudson Pearlie M.,
Suh Harold H.,
Ye Hong,
Tuominen Raimo K.,
Hong John S.
Publication year - 1993
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1993.tb03541.x
Subject(s) - angiotensin ii , protein kinase c , phospholipase c , medicine , endocrinology , angiotensin receptor , phorbol , angiotensin ii receptor type 1 , chemistry , losartan , receptor , biology , biophysics , biochemistry , signal transduction
The relative contributions of Ca 2+ influx and intracellular Ca 2+ mobilization were examined for angiotensin II‐stimulated [ 3 H]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 shortlived mobilization of intracellular Ca 2+ . Angiotensin II‐stimulated [ 3 H]phorbol 12, 13‐dibutyrate binding was largely blocked in Ca 2+ ‐free buffer and by pretreatment with the Ca 2+ ‐channel blocker ω‐conotoxin GVIA. The [ 3 H]phorbol 12, 13‐dibutyrate binding response to [Sar 1 ]angiotensin II also appeared to be voltage sensitive, as no additivity was observed with the response to the depolarizing agent 4‐aminopyridine (3 m M ). 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 (AT 1 ‐Iike) receptors. The dependence of angiotensin II‐stimulated [ 3 H]phorbol 12, 13‐dibutyrate binding on extracellular Ca 2+ 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.