The Depolarization of Nearve by Organic Compounds. ∗

Summary

Depolarization produced by a variety of organic reagents acting on frog sciatic nerve has been measured. With the alcohols, the fact that the lower alcohols depolarize before blocking nerve, whereas higher block conduction before depolarizing, is referable to the, abnormally high activity coefficients of methanol and ethanol in nonaqueous solvents, and hence to the high aqueous mole fractions necessary for narcosis. While the alcohols depolarize at aqueous activities of about 0.15-0.30, other organic substances, of a relatively non-polar nature, depolarize only at activities of about 0.8. Such substances show a surface tension depression similar to that of the alcohols at these elevated thermodynamic activities. The distinction is made between narcosis, which requires a given mole fraction of a substance in the nonaqueous phase of the fiber, and depolarization which requires a given depression of the inter-facial tension.