Correlation of local cerebral blood flow, glucose utilization, and tissue pH following a middle cerebral artery occlusion in the rat

The use of three sets of the double-tracer autoradiographic technique to measure topographical changes of local cerebral blood flow (LCBF), glucose utilization (LCGU), and tissue pH following a 3 h middle cerebral artery (MCA) occlusion in the rat is described. In a sham-operated group of animals there was 10% reduction of LCBF and 7% reduction of LCGU in the most affected areas as compared to the contralateral homologous regions. However, the ratio of LCGU/LCBF in the affected areas remained within normal limits. In the MCA-occluded animals, LCGU showed a bimodal response to decreased LCBF. LCGU decreased with reduced LCBF until LCBF fell to 38% of normal. Below this LCBF level LCGU increased, most likely implying anerobic glycolysis. Decline of tissue pH corresponds to the mismatch of LCBF and LCGU. These results suggest that brain tissue pH change cannot be predicted on the basis of LCBF or LCGU alone