[Tissue pH and energy metabolism in cerebral embolization model of rat]

Changes in brain tissue pH, ATP and NADH contents in the cerebral embolization model of Wistar rat were investigated by bioluminescence method. Under light anesthesia, main trunk of cerebral artery was embolized with a silicone cylinder (500 microns in diameter and 1 mm in length) through the cervical internal carotid artery. Rat brain was frozen in situ at 1 or 3 hours after embolization. In some rats Evans blue was injected into the peritoneal cavity 30 minutes before freezing. Caudate putamen and cortex were often acidotic but thalamus, hypothalamus, and hippocampus were composed of both acidotic and alkalotic area. Exudation of Evans blue was frequently detected in the alkalotic area. ATP was decreased partially in the acidotic area. In the alkalotic area ATP was decreased to mild to severe degree. Decreased ATP region in the acidotic area showed increased NADH content, whereas in the alkalotic area NADH was diffusely decreased. From these results, alkalosis may be induced by cerebral edema due to plasma exudation. The decrease of ATP and increase of NADH in the acidotic area may demonstrate the disturbance of oxidative phosphorylation under anaerobic glycolysis, and the decrease of ATP and decrease of NADH in the alkalotic area may demonstrate impairment of glycolysis mainly due to brain edema.