Department of Dental Pharmacology, School of Dentistry, Iwate Medical University
Abstract
The present study clearly demonstrated the effects of complete cerebral ischemia and selective ischemia on brain choline metabolism in ddY mice The complete cerebral ischemia mouse was produced by cervical dislocation, and the selective ischemia mouse was produced by bilateral occlusion of the common carotid arteries. The following results were obtained 1 Complete cerebral ischemia increased brain choline contents rapidly and remarkably for 10 minutes After 10 minutes, the rate of increase of brain choline contents suddenly fell. 2 The increased level of choline contents by complete cerebral ischemia differed among the brain regions (cerebral cortex, hippocampus, medulla oblongata, cerebellum) tested 3 Selective ischemia increased choline contents in the cerebral cortex and hippocampus but not in the medulla oblongata or cerebella. 4. As with complete ischemia, hypoxia induced by N_2 gas inhalation increased choline contents in all brain regions. 5. Hypoglycemia induced by insulin administration did not increase brain choline contents However, the ischemia under a hypoglycemia state produced a greater choline increase than ischemia alone 6 Complete cerebral ischemia decreased the contents of both phosphatidylcholme (PtdCh) and glycerophosphocholine (GlyCh) in the mouse brain. The present results suggest that a main cause for the ischemic increase of brain choline contents is hypoxia by cessation of blood flow, and a low energy state caused by hypoglycemia partly contributes to this increase Furthermore, it is suggested that the ischemic increase of brain choline depends on the choline accumulation that results from decomposition of both PtdCh and GlyC
