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Effects of Ethanol on Phosphorylation of Lipids in Rat Synaptic Plasma Membranes
Author(s) -
Tong Wei,
Sun Grace Y.
Publication year - 1996
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1996.tb01131.x
Subject(s) - phosphatidic acid , phosphatidylinositol , chemistry , ethanol , incubation , biochemistry , phosphorylation , diacylglycerol kinase , membrane , phospholipid , protein kinase c
Synaptic plasma membranes (SPM) isolated from rat cerebral cortex contain lipid kinases for conversion of phosphatidylinositol (PI), phosphatidylinositol 4‐phosphate (PIP), and diacylglycerol (DG) to PIP, phosphatidylinositol 4,5‐bisphosphate (PIP 2 ), and phosphatidic acid (PA), respectively. These anionic phospholipids are important in signal transduction mechanisms and are required for synaptic function. The effect of ethanol and other aliphatic alcohols on phosphorylation of these lipids in SPM has not been established. incubation of SPM with [Y 32 P]ATP resulted in labeling of PIP, lyso‐PIP, PIP 2 , and PA. Ethanol (50–200 mM) added to the incubation system showed a dose‐dependent decrease in labeling of PIP 2 but not PIP or PA. To a lesser extent, labeling of PIP 2 was also inhibited by 1‐propanol, but neither isopropanol nor 1‐butanol could alter the PIP 2 labeling pattern. Under similar incubation conditions, labeling of PIP and PA in SPM was not altered by ethanol, 1‐propanol, isopropanol, but l‐butanol stimulated PIP labeling with a peak at 25 mM. Addition of exogenous PIP to the incubation mixture led to an increase in labeling of PIP 2 , suggesting that the endogenous PIP pool in SPM is limiting for the synthesis of PIP 2 in SPM. Interestingly, when SPM were incubated with exogenous PIP, addition of ethanol (50–100 mM) to this incubation mixture resulted in an increase in PIP 2 labeling. Taken together, these results suggest a specific effect of ethanol on PIP kinase in SPM, and this effect seems to be dependent on the location and/or amount of PIP in the membrane.