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Muscarinic Acetylcholine Receptor Enhances Phosphatidylcholine Hydrolysis via Phospholipase D in Bovine Chromaffin Cells in Culture
Author(s) -
Carmen García María,
López Manuela G.,
García Antonio G.,
Crespo Mariano Sánchez
Publication year - 1992
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.1471-4159.1992.tb10117.x
Subject(s) - diacylglycerol kinase , phosphatidic acid , phosphatidylcholine , muscarinic acetylcholine receptor , oxotremorine , diacylglycerol lipase , chemistry , acetylcholine , phospholipase d , phospholipase c , diglyceride , second messenger system , biochemistry , phospholipase , endocrinology , biology , phospholipid , receptor , protein kinase c , signal transduction , enzyme , membrane
Although it is well‐established that inositol‐containing lipids serve as precursors of intracellular second messenger molecules in chromaffin cells, we describe some findings that show the formation of diacylglycerol from phosphatidylcholine in response to agonist‐mediated stimulation. Stimulation of chromaffin cells by acetylcholine produced a high turnover of phosphatidylcholine, as suggested by the release of [ 3 H]choline derived from [ 3 H]‐phosphatidylcholine in experiments performed with [ 3 H]choline chloride‐prelabeled cells. An enhanced breakdown of phosphatidylcholine was also inferred from the finding of an increased formation of [ 3 H]diacylglycerol in chromaffin cells prelabeled with [ 3 H]glycerol. The diacylglycerol mass that accumulated after stimulation showed a distinct temporal course and seemed to exceed the mass that has been reported to be derived from phosphatidylinositol. In keeping with the purported origin from phosphatidylcholine, diacylglycerol showed a high content in [ 3 H]oleate molecular species. Phospholipase D activity measurements and experiments performed in the presence of propranolol (an inhibitor of phosphatidic acid:phosphohydrolase) suggested that phosphatidylcholine is hydrolyzed by a phospholipase D activity, producing phosphatidic acid, which is subsequently degraded to diacylglycerol, rather than by a phospholipase C. Incubation of chromaffin cells in the presence of atropine before addition of acetylcholine showed complete inhibition of the increased formation of [ 3 H]‐diacylglycerol, whereas d ‐tubocurarine failed to do so. Taken together, these results suggest that acetylcholine activates phosphatidylcholine breakdown and diacylglycerol formation in chromaffin cells via a muscarinic‐type receptor.