THE CYTOCHROME REDOX STATE IN GUINEA-PIG CORTICAL BRAIN-SLICES ELICITED BY TETANIC STIMULATION

The relationship between the production and consumption systems of ene rgy-rich phosphates (ATP, adenosine triphosphate) was investigated in slices of guinea-pig olfactory cortex by an electrical method and spec trophotometry. Potentials from brain slices were evoked by the orthodr omic and repetitive stimulation of the lateral olfactory tract. The ch anges in the evoked potential amplitudes induced by various modes of e lectrical stimulus frequency and duration, were regarded as the consum ptive index of ATP On the other hand, the nervous tissues became hypox ic when ATP was aerobically produced during the acceleration of oxygen consumption in mitochondrial oxidative phosphorylation process. This hypoxic state caused the redox state of the cytochromes to shift to th e reduction side, so the shift was thought to reflect the kinetics of the production of bioenergic metabolites. The generation of evoked pot entials and the kinetic changes in the cytochromes redox state levels suggested mutual interactions between the productive and consumptive s ystems of ATP.