Properties of axon membrane as affected by cobra venom, digitonin, and proteases

Abstract

Electrical excitability and electrical constants of the lobster axon membrane have been measured under the influence of externally applied cobra venom, digitonin, or proteases in an attempt to gain insight into the molecular nature of membrane excitation. After the cobra venom which contained phospholipase A or after digitonin, resting potential, action potential, threshold potential, and membrane resistance decreased, while membrane capacity increased at least temporarily. After a mixture of trypsin and α-chymotrypsin, all of the parameters were kept almost unchanged. The results are in favor of the view that membrane phospholipid integrity is essential for the maintenance of membrane potential and excitability.