Cyclic AMP induces ryanodine-sensitive Ca2+ release from microsomal vesicles of rat parotid acinar cells.
The effect of cAMP on a ryanodine-sensitive Ca2+ release from microsomal vesicles of rat parotid acinar cells was studied. After a steady state of ATP-dependent 45Ca2+ uptake into the vesicles, cAMP was added to the medium with thapsigargin (TG) to block a reuptake of 45Ca2+. The addition of cAMP (1.0 mM) with TG released about 10% of the 45Ca2+ that had been taken up. The cAMP-induced 45Ca2+ release was strongly inhibited by pretreatment of the vesicles with 500 microMM ryanodine. Preincubation with cAMP (1 mM) abolished ryanodine (10 microM)-induced 45Ca2+ release. The presence of a specific inhibitor of cAMP-dependent protein kinase (PKA) H-89 (10 microMM) inhibited the cAMP-induced 45Ca2+ release. These results indicate that in rat parotid acinar cells, cAMP can activate a ryanodine-sensitive Ca2+ release mechanism in the endoplasmic reticulum and that this activation is via a PKA-dependent process.
Ozawa
T
T
Department of Physiology, Tohoku University School of Medicine, Sendai, Japan.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D000242:Cyclic AMP / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012433:Ryanodine / Q000494:pharmacology*; D013449:Sulfonamides; D019284:Thapsigargin / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007546:Isoquinolines; D013449:Sulfonamides; C071449:H 85; D012433:Ryanodine; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D006493:Heparin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000252:Calcium-Transporting ATPases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D002118:Calcium