Induction of electrical excitability in crustacean muscle by 4-cyclopentene-1,3-dione

4-Cyclopentene-1,3-dione induces electrical activity in inexcitable crustacean muscle. This effect is blocked by previous treatment with p-chloromercuribenzoic acid. These results suggest that crustacean muscle becomes excitable when certain -CH2-SH side chains are converted to thioethers having carbonyl groups.