On the mechanism of the potassium loss from brain slices induced by cholinesterase inhibitors

A number of reports have appeared suggesting that cholinesterase plays an important role in relation to cell membrane permeability. Rothenberg (1950) and Grundfest & Nachmansohn (1950), for example, have shown that the cholinesterase inhibitors diisopropylphosphorofluoridate (DFP) and eserine in concentrations of about 0'02M increase the exchange of radioactive sodium (24Na) between the axoplasm of giant squid axons and sea water containing the 24Na, and that DFP decreased the exchange of radioactive potassium (42K) under similar conditions. These results were interpreted as showing an increase in ion permeability of the axon, and it was suggested that the cholinesterase system may be important in this connexion.