NADH fluorescence, [K +] 0 and oxygen consumption in cat cerebral cortex during direct cortical stimulation

Abstract

NADH fluorescence, sagittal sinus blood flow and sinus hemoglobin saturation were monitored simultaneously during direct cortical stimulation of a wide area of the anterior and mid suprasylvian and marginal gyri. The area monitored fluoremetrically was located within the area apparently drained by the sinus, so that the fluorometric changes could be correlated with oxygen consumption changes calculated from the sinus flow and saturation values. The onset and peak values of calculated oxygen consumption and NADH fluorescence changes usually occured within several seconds of one another and high, significant ( r > 0.9andP < 0.01) correlations were found between the maximum changes in both parameters following stimulation. The relation of cortical [K +] 0 changes to oxygen consumption changes was also explored; again the magnitude of [K +] 0 changes and calculated oxygen consumption changes correlated well. The demonstrated agreement between fluorometric and direct (sinus cannulation) measurements of oxidative metabolism reinforces the interpretation of in situ cortical fluorescence changes as indicative of changes in oxygen consumption rate.