title: Staurosporine inhibits inositol phosphate formation in bovine adrenal medullary cells.
abstract: The effect of protein kinase C activators and inhibitors on histamine-stimulated phospholipase C in bovine adrenal medullary cells has been investigated. The protein kinase C activators, phorbol 12,13-dibutyrate (PDB) or sn-1,2-dioctanoylglycerol (DOG), inhibited histamine-stimulation of phospholipase C. This inhibition was prevented by the protein kinase C-selective inhibitor Ro 31-8220 (3-[1-[3-(2-isothioureido) propyl]indol-3-yl]-4-(1-methylindol-3-yl)-3-pyrrolin-2,5-dio ne) but not the broad spectrum protein kinase inhibitor staurosporine. Indeed staurosporine on its own inhibited both the histamine-stimulated response and, in permeabilized cells, phospholipase C activated by Ca2+. Staurosporine inhibition of phospholipase C is unlikely to be mediated via protein kinase A or Ca2+/calmodulin-dependent protein kinase because it was not reproduced by selective inhibition of these kinases. Staurosporine treatment, however, reduced inositol phospholipid levels in stimulated cells. Thus staurosporine and Ro 31-8220, two widely used protein kinase C inhibitors, have quite different effects on phospholipase C activation. Furthermore, staurosporine may cause this inhibition through a reduction in the level of phospholipase C substrate.
authors.affiliation: Neuroscience Group, Faculty of Medicine, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: S J
authors.initials: SJ
authors.lastname: Bunn
authors.forename: H I
authors.initials: HI
authors.lastname: Saunders
mesh_terms: D000313:Adrenal Medulla / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors; D002417:Cattle; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D003864:Depression, Chemical; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007295:Inositol Phosphates / Q000096:biosynthesis*; D007546:Isoquinolines / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine; D013449:Sulfonamides; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D000470:Alkaloids; D002147:Calmodulin; D004791:Enzyme Inhibitors; D007211:Indoles; D007295:Inositol Phosphates; D007546:Isoquinolines; D013449:Sulfonamides; D006632:Histamine; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010738:Type C Phospholipases; D019311:Staurosporine; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C064758:Ro 31-8220; D009638:Norepinephrine