[The influence of 2,4-dichlorphenoxyacetate (2,4-D) on the membrane potential, membrane resistance and electromyogram of the frog skeletal muscle before and after stimulation (author's transl)].

The influence of 2,5-Dichlorphenoxyacetate (2,4-D) on the membrane potential, membrane resistance and electromyogram of the isolated frog skeletal muscle was studied. The membrane potential and membrane resistance were measured in the rest and after an impulse series of 10 impulses which was applicated with 1 impulse/s. The membrane resistance was not significantly variable. The membrane potential decreased about 30 mV when the muscle was 4 hours in 2,4-D (Fig. 1). At rest the membrane potential as well as the muscle in a solution with and without 2,4-D had constant values when the muscle was only a short time in 2,4-D. But when the muscle was stimulated several times with 1 impulse/s the membrane potential decreased about 20 mV. After a time of 30 s the normal value of the rest-potential was reached again. The effects induced by 2,4-D were reversible in Ringer-solution (Fig. 2). These findings are discussed and beside changes in conductances the role of the Ca-ions is also mentioned as a possible cause. An anomalous temporary binding of ions on the membranes of the muscle is assumed.