Reactivity to acetylcholine developed by artificial membranes containing a protein from Electrophorus electricus: the effect of uranyl ions

A special hydrophobic protein fraction from the electroplax of $\text{Electrophorus}\text{electricus}$, when incorporated into artifical lipid membranes, induces a reactivity to acetylcholine. Uranyl ions increase 10–20 times the conductivity of such membranes, produce discrete current jumps, and strongly potentiate the effect of acetylcholine. The response to acetylcholine was studied in media containing KCl,NaCl, Choline-Cl and Na-Propionate in the presence or absence of uranyl ions. control membranes made of lipids or containing a non-cholinergic protein from the same tissue showed no reactivity to acetylcholine and had only a slight increase in conductance at very high concentrations of uranyl ions.