ACETYLCHOLINESTERASE AND NA+,K+-ATPASE ACTIVITIES IN DIFFERENT REGIONS OF RAT-BRAIN DURING INSULIN-INDUCED HYPOGLYCEMIA

The activities of acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7), responsible for hydroylsis of acetycholine and Na+,K+-ATPase (Mg2+-dependent ATP phosphohydrolase, EC 3.6.1.3), which plays a crucial role in neurotransmission, were determined in four brain regions after 1, 2, and 3 h of insulin adminstration. Significant decrease in the acetylcholinesterase and Na+,K+-ATPase activities was observed in the soluble and total particulate fractions from cerebral hemispheres, cerebellum, brain stem, and diencephalon + basal ganglia after 1, 2, and 3 h of insulin-induced hypoglycemia. Blood glucose level decreased significantly after 1 h of insulin administrationand remained at low level for 2 h thereafter; whereas, the protein content in different subcellular fractions from four brain regions did not show any significant change under this physiological stress.