A distinct 2,5-di-(tert-butyl)-1,4-benzohydroquinone-sensitive calcium store in bovine adrenal chromaffin cells.
The fluorescent Ca2+ indicator Fura 2 was used to monitor Ca2+ release induced by the Ins(1,4,5)P3-mobilizing agonist angiotensin II (Ag II), caffeine and 2,5-di-(tert-butyl)-1,4-benzohydroquinone (tuBHQ), in intact bovine adrenal chromaffin cells. Under low external Ca2+ conditions, tuBHQ, Ag II and caffeine elicited Ca2+ rises, indicating Ca2+ release from internal stores. Prior addition of Ag II had no noticeable effect on the extent of release of Ca2+ induced by tuBHQ. Stimulation of the cells with tuBHQ before either Ag II or caffeine, similarly had no effect on Ca2+ released by these two agonists. It was concluded, therefore, that there is a third intracellular Ca2+ store in bovine adrenal chromaffin cells, distinct and non-overlapping, from those sensitive to caffeine or Ins(1,4,5)P3-mobilizing agonists.
Department of Physiology, University of Liverpool, UK.
I M
IM
Robinson
R D
RD
Burgoyne
D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D016257:Fura-2; D006873:Hydroquinones / Q000494:pharmacology*; D007700:Kinetics; D013050:Spectrometry, Fluorescence
D006873:Hydroquinones; D000804:Angiotensin II; C019359:2,5-di-tert-butylhydroquinone; D002110:Caffeine; D002118:Calcium; D016257:Fura-2