Brain tissue acidosis and changes of energy metabolism in mild incomplete ischemia--topographical study.

Regional changes of brain tissue pH and its correlation to energy metabolism were studied in various degrees of incomplete ischemia for 5 and 60 min in the unilateral common carotid occlusion of normally fed mongolian gerbils. The degree of ischemia was evaluated by the severity of neurological deficits following 60 min of occlusion, and animals were divided into three groups: symptomatic, borderline, and asymptomatic. Changes of NADH and ATP distribution corresponded well to the degree of ischemia. On the other hand, acidosis developed more clearly and extended in wider areas than the changes of NADH and ATP distribution. These changes were already seen at 5 min of occlusion. From the results of this experiment, it was suspected that acidosis in mild incomplete ischemia was due to stimulated anaerobic glycolysis that might supplement NADH oxidation and ATP yields. Further, acidosis without energy failure was considered not to be detrimental to neuronal cells.