Simultaneous bilateral laser Doppler fluxmetry and electrophysiological recording during middle cerebral artery occlusion in rats.

Laser Doppler fluxmetry (LDF) and electrocorticography (ECG) are techniques used to indicate successful occlusion of the middle cerebral artery (MCAO) in the intraluminal filament model of ischemic stroke. However, each method has several advantages and drawbacks. This article describes a simple technique to simultaneously and continuously monitor LDF and ECG over both cerebral hemispheres. We investigated the potential of this method to improve the reliability of the filament model. Thirty male Sprague-Dawley rats were subjected to transient MCAO under three different experimental conditions (n=10 each group): MCAO in [A] normothermic animals, in [B] animals treated with hypothermia and in [C] animals receiving barbiturate for induction of burst suppression. Cortical blood flow was continuously recorded bilaterally by LDF and the electrocorticogram was continuously recorded over both hemispheres. The results show that monitoring of cortical electrophysiological activity by ECG allows detection of subarachnoid hemorrhage (SAH) during normal electrophysiological status and provides continuous control of barbiturate induced burst suppression as well as information about postischemic electrophysiological recovery. ECG did not detect MCAO, premature reperfusion, or SAH during burst suppression induced by barbiturates. In contrast, MCAO, SAH and premature reperfusion were rapidly indicated by LDF. Our findings suggest that simultaneous bilateral LDF and ECG during MCAO are of complementary value, in particular if barbiturates are investigated.