Effect of Dilantin and Mesantoin on the Giant Axon of the Squid.

Abstract

The giant axon of squid was dissected in connection with its ganglion. The addition of dilantin and mesantoin to a perfusion of artificial sea water does not affect the electrical activity of isolated giant axons. In the presence of reduced Ca and Mg spontaneous firing of the fiber occurs. This reaction is reversible. A decrease in hy-perirritability may also be obtained by adding dilantin or mesantoin to water deficient in Ca and Mg. Dilantin labelled with N15 penetrated into the interior of the giant axon. The concn. in the axoplasm of the fiber was close to equilibrium within 1 hr.