Three-dimensional redox image of the normal gerbil brain

Regional differences in the redox ratio were studied in the gerbil brain. B rains were frozen using an ill situ funnel-freezing method, and sliced coro nally for scanning of mitochondrial redox imaging. The relative local redox ratio of nicotinamide-adenosine dinucleotide to its reduced form was calcu lated from fluorescence signals of intrinsic fluorochromes, i.e. reduced ni cotinamide-adenosine dinucleotide and flavoproteins, using a high resolutio n fluorometer developed in our laboratory. Twelve consecutive coronal image s were obtained from each of 10 gerbils. The mean value of the regional red ox ratio in both the cerebral and cerebellar gray matter were found to be s ignificantly lower than that in the cerebral and cerebellar white matter (P < 0.01, Mann-Whitney test). Local differences in the redox ratio were also found among subregions of gray matter. The redox ratio in the globus palli dus was significantly higher than values in other subregions of gray matter (P < 0.01, Mann-Whitney test) We postulate that a high concentration of the reduced form of pyridine nucl eotide is maintained to provide redox energy for rapid turnover of ATP in t he areas of high energy consumption. (C) 1999 IBRO. Published by Elsevier S cience Ltd.