ABSTRACT
Free fatty acids (FFA) and diacylglycerol (DG) content and composition in the cerebrum of 5-day-old rats were studied after pentylenetetrazol (PTZ)-induced convulsions. A threefold increase in brain FFA was observed 30 min after PTZ injection in experiments carried out in spring. In contrast, a 50% decrease in FFA content was observed during summer. These changes were accounted for by saturated and monoenoic fatty acids, whereas arachidonic and docosahexaenoic acids were not affected during the convulsive episode in either season. The effect of PTZ on brain DG was much smaller than it was on FFA, and less sensitive to seasonal influence. However, DG released in the summer was significantly less enriched in arachidonic acid than in the spring. Levels of FFA and DG in untreated animals were found to be subject to a circannual rhythm. Both the levels of FFA and their degree of unsaturation (unsaturated fatty acids/total FFA) were highest in summer and lowest in winter, whereas the opposite was true for DG. Circannual variations in these metabolites may be the manifestation of a programmed biological calendar regulating enzymes of brain lipid metabolism in homeotherms that under natural conditions must adapt to changing environmental temperatures.
Subject(s)
Brain Chemistry , Diglycerides/analysis , Fatty Acids, Nonesterified/analysis , Glycerides/analysis , Pentylenetetrazole , Seasons , Seizures/metabolism , Animals , Brain/growth & development , Brain Chemistry/drug effects , Fatty Acids, Unsaturated/analysis , Female , Pregnancy , Rats , Rats, Inbred Strains , Seizures/chemically inducedSubject(s)
Arachidonic Acids/metabolism , Brain/metabolism , Membrane Lipids/metabolism , Status Epilepticus/metabolism , Animals , Arachidonic Acid , Bicuculline , Cerebellum/metabolism , Diglycerides/metabolism , Fatty Acids, Nonesterified/metabolism , Female , Rats , Rats, Inbred Strains , Status Epilepticus/chemically inducedABSTRACT
Bicuculline-induced status epilepticus was found to be associated with increased amounts of free fatty acids and diacylglycerols in the rat cerebrum. The predominant fatty acid in both lipid pools was arachidonic acid. The accumulation of arachidonoyl-diglycerols decreased at the time of and during behavioral seizures induced by bicuculline, while the amount of free arachidonic acid appeared to increase. We propose a metabolic relationship between these lipids to explain the described changes. The similarities between the composition of the lipid pools and the fatty acid composition of phosphatidylinositol support the hypothesis that these changes may be a result of a convulsion-activated degradation of this phospholipid from excitable membranes.
