Effect of pentobarbital on regional brain phospholipid synthesis

Rats were given 45 mg/kg i.p. sodium pentobarbital 15 min prior to the intraventricular injection of 200 μCi [³²P]phosphoric acid and 50 μCi [³H]glycerol. The animals were sacrificed 1 hr later, subcellular fractions were prepared from four subcortical brain regions and phospholipids were extracted. Pentobarbital significantly increased the ratio of [³H]- and [³²P]-triphosphatidylinositol (TPI) to diphosphatidylinositol (DPI) in the microsomal but not synaptosomal fractions. The possible relationship of this change to nicotinic receptor activity is discussed. Pentobarbital specifically decreased ³²Pi but not [³H]glycerol incorporation into synaptosomal phosphatidylinositol (PI). Thus, pentobarbital induced the opposite of the "neurotransmitter effect" on PI turnover. Pentobarbital either decreased or had no effect on the incorporation of ³²Pi and [³H]glycerol into phosphatidylserine (PS), phosphatidylcholine (PC) and phosphatidylethanolamine (PE).