The Release of Phosphate From the Electric Organ of Torpedo

Abstract

ABSTRACT A technique is described for perfusing the isolated electric organ of Torpedo. With a constant perfusion pressure the admission of acetylcholine is found to cause an appreciable reduction in the rate of flow. Orthophosphate, sulphate, glutamate and aspartate have been identified as anions which pass from the electric organ into the fluid perfusing through it. With a perfusion rate of 4-8 ml./min., repetitive stimulation of the nerve caused an increase in the rate of phosphate released from the organ. The phosphate concentration in the venous effluent rose to a maximum of about 180% of the resting level, and stimulation to exhaustion resulted in the release of an additional 10 μmol. of phosphate. Perfusion of an electric organ by acetylcholine elicited a slowly developing response amounting at the most to about 1 mA. when passed into a low resistance and lasting for about 7 min. The possible role of intra-electroplate anions in generating the discharge of the Torpedo electric organ is discussed. The additional phosphate released from the organ on stimulation accounts for only 1 % of the charge which crosses the active electroplate membrane.