Tetraenoic species are conserved in muscarinically enhanced inositide turnover.
Carbamylcholine enhances the labeling of phosphatidate and phosphatidylinositol from 32Pi in nerve endings. Approximately 74% of labeled phosphatidate and 85% of labeled phosphatidylinositol produced on muscarinic stimulation are accounted for by tetraenoic species, as detected by argentation TLC. Incubation of membranes derived from nerve endings with [gamma-32P]ATP under conditions of phosphodiesteratic degradation of endogenous polyphosphoinositides resulted in increased labeling of phosphatidate. Approximately 78% of the newly formed phosphatidate was in a tetraenoic fraction. It is concluded that in muscarinically stimulated nerve endings, the diacylglycerol moiety is conserved following diacylglycerol release from polyphosphoinositides through its resynthesis to inositol lipid via phosphatidate.
Van Rooijen
L A
LA
Hajra
A K
AK
Agranoff
B W
BW
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002540:Cerebral Cortex / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D006168:Guinea Pigs; D007295:Inositol Phosphates / Q000378:metabolism; D009411:Nerve Endings / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*
D004075:Diglycerides; D007295:Inositol Phosphates; D010712:Phosphatidic Acids; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D011976:Receptors, Muscarinic; C037178:phosphatidylinositol 4-phosphate; D002217:Carbachol