ACTION POTENTIAL AND ENZYME ACTIVITY IN THE ELECTRIC ORGAN OF ELECTROPHORUS ELECTRICUS. II. PHOSPHOCREATINE AS ENERGY SOURCE OF THE ACTION POTENTIAL

Abstract

Breakdown of phosphocreatine and formation of lactic acid as a result of the discharge were detd. on the electric organ of Electrophorus electricus. The energy supplied by these 2 chemical processes was compared with the electrical energy released. The following results were obtained. The external electrical energy/g. of tissue and impulse is on the avg. 8.2 X 10-6 g. calories, The total electrical energy is at least twice as high. The amt. of phosphocreatine split supplies/g. and impulse on the avg. 32.8 X 10-6 g. calories, that is 4 times as much as the external electrical energy. The amts. of acetylcholine and phosphocreatine metabolized as result of the discharge are of the same order of magnitude. This suggests that the energy of phosphate bonds is used for the resynthesis of acetylcholine. The discharge leads also to lactic acid formation supplying an energy of 16.8 X 10-6 g. calories/g. and impulse. The chains of reactions supplying the energy required to restore the resting condition of the electric organ thus appears to be fundamentally identical with those which are the source of energy in muscle contraction.