EVALUATION OF <i>IN SITU</i> FREEZING OF CAT BRAIN BY NADH FLUORESCENCE

Abstract

Abstract— Cat brain was frozen in situ with liquid nitrogen. In order to locate areas with ischemic artifact, frozen brain slices were surveyed for regions of increased NADH fluorescence. In addition, levels of ATP, phosphocreatine, lactate, and NADH were determined in various brain regions. High levels of ATP and phosphocreatine, and low levels of lactate and NADH were present in all brain regions except the depths of some cortical sulci. These regions of ischemic change were easily detected by virtue of increased NADH fluorescence in frozen brain slices. Deep brain structures such as basal ganglia and hippocampus showed neither high tissue fluorescence nor ischemic changes of the metabolites measured. Therefore, in situ freezing of cat brain adequately preserves metabolite levels in most regions.