Potentiation by lithium of CMP-phosphatidate formation in carbachol-stimulated rat cerebral-cortical slices and its reversal by myo-inositol.
This paper describes a rapid and simple method for measuring CMP-phosphatidate (CMP-PA; CDP-diacylglycerol), providing a novel assay for inositol phospholipid metabolism. Rat cerebral-cortical slices labelled with [14C]cytidine were incubated with the muscarinic cholinergic agonist carbachol in the presence of various concentrations of LiCl; 10 mM-LiCl greatly enhanced the carbachol-stimulated formation of [14C]CMP-PA over a 60 min incubation period. The potentiation by Li+ was concentration-dependent, with a maximal enhancement at 3 mM and half-maximal enhancement at 0.6 mM-LiCl. The enhancement by Li+ could be reversed by incubation with myo-inositol; a maximal effect was observed with 10 mM-inositol. A similar, though smaller, enhancement of CMP-PA concentrations in the presence of LiCl was observed in slices stimulated with noradrenaline, 5-hydroxytryptamine and K+. The results are discussed in relation to previously observed effects of Li+ on inositol phospholipid metabolism.
Godfrey
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PP
M.R.C. Unit, Radcliffe Infirmary, Oxford, U.K.
D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D003567:Cytidine Diphosphate Diglycerides / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007294:Inositol / Q000494:pharmacology*; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D009702:Nucleoside Diphosphate Sugars / Q000096:biosynthesis*; D010716:Phosphatidylinositols / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains
D003567:Cytidine Diphosphate Diglycerides; D009702:Nucleoside Diphosphate Sugars; D010716:Phosphatidylinositols; D007294:Inositol; D002217:Carbachol; D008094:Lithium