Actions of electrical stimulation and of 2:4-dinitrophenol on the phosphates in sections of mammalian brain in vitro

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Abstract
Procedures were developed for sampling, within half a minute, sections of cerebral cortical tissue to which potential gradients were applied during in vitro metabolism. The potential gradients which caused increased respiration and glycolysis in sections of mammalian brain caused also a fall in their content of creatine phosphate and a rise in that of inorganic phosphate. The changes in phosphates could be induced by stimulation at different times during the in vitro metabolism. By stopping the stimulation and maintaining good metabolic conditions for about 15 min. the inorganic and creatine phosphates were partly restored to their previous, unstimulated values. The increase in respiration caused by 2, 4-dinitrophenol was maximal at about a 5 x 10-5 [image] concn. (approx. 20 mg. tissue/ml. fluid). The max. value was approx. equal to the max. respiration caused by electrical stimulation. The 2 effects, when each was approaching its max., were not additive; potential gradients normally stimulatory had negligible effects when applied to a slice metabolizing in the presence of 5 x 10-5 [image] dinitrophenol. 2, 4-Dinitrophenol also caused a fall in the creatine phosphate and a rise in the inorganic phosphate of brain cortex slices. It was very prompt in doing this, having a large effect within 2 min. of its addition.