Enhanced inositide turnover in brain during bicuculline-induced status epilepticus.
Because brain inositides are enriched in the 1-stearoyl-2-arachidonoyl species, they form a likely source for the tetraenoic free fatty acids (FFA) and diacylglycerols (DG) that are accumulated during seizures. To study inositide turnover during bicuculline-induced seizures, rats were injected intraventricularly and bilaterally with 10-20 microCi 32P, mechanically ventilated and sacrificed by 6.5 KW head-focused microwave irradiation. Seizure activity was recorded by electroencephalography. Bicuculline-induced seizure activity resulted in: a) almost 50% increase in 32P labeling of phosphatidic acid (PA); phosphatidylinositol (PI) and phosphatidylinositol 4,5-bisphosphate (PIP2) also increased (24% and 36%, respectively); b) no change in other lipids; and c) water-soluble phosphodiesteratic degradation products, analyzed by high voltage paper electrophoresis, increased 24% in the amount of radiotracer recovered as inositol 1,4-bisphosphate (IP2) and by 44% in the amount recovered as inositol 1,4,5-trisphosphate (IP3). These data indicate that during experimental status epilepticus the cerebral inositide cycle is accelerated: PIP2----(IP3----IP2----IP----I) + DG----PA----PI----PIP----PIP2.
D000818:Animals; D001640:Bicuculline; D001921:Brain / Q000378:metabolism*; D004075:Diglycerides / Q000378:metabolism; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D008297:Male; D010712:Phosphatidic Acids / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D004075:Diglycerides; D005230:Fatty Acids, Nonesterified; D010712:Phosphatidic Acids; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; D001640:Bicuculline