A protein kinase C-dependent mechanism(s) is involved in atropine-resistant accumulation of diacylglycerol in rat parotid gland.
We investigated the atropine-resistant accumulation of sn-1,2-diacylglycerol (DAG) on stimulation of 1 microM carbachol (CCh) in parotid acinar cells. CCh-induced DAG accumulation was biphasic, peaking at 5 and 20 min. Atropine inhibited two peaks in a dose-dependent manner, but the first peak was inhibited much more than the second one. Atropine (10 microM) completely inhibited both DAG accumulation and the breakdown of phosphatidylinositol 4-monophosphate and 4,5-bisphosphate (PIP2) 5 min after stimulation with CCh. In contrast, the breakdown of PIP2 at 20 min was completely inhibited by 10 microM atropine, but DAG accumulation was not. This atropine-resistant component at 20 min is significantly inhibited by staurosporine, a protein kinase C inhibitor. These results suggest that atropine-resistant accumulation of DAG at 20 min derives directly from other lipids rather than phosphoinositides and is regulated by a protein kinase C-dependent mechanism(s).
Komabayashi
T
T
Department of Physiology and Pharmacology, Tokyo College of Pharmacy, Japan.
Yakata
A
A
Izawa
T
T
Suda
K
K
Tsuboi
M
M
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology; D004075:Diglycerides / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D008297:Male; D010306:Parotid Gland / Q000166:cytology / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D019311:Staurosporine; D013997:Time Factors
C011439:1,2-diacylglycerol; D000470:Alkaloids; D004075:Diglycerides; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C037178:phosphatidylinositol 4-phosphate; D001285:Atropine; D002217:Carbachol; D011493:Protein Kinase C; D019311:Staurosporine