EFFECTS OF THE INSECTICIDE DECAMETHRIN ON ACTION POTENTIAL AND VOLTAGE-CLAMP CURRENTS OF MYXICOLA GIANT-AXON

1. The effects of the externally applied insecticide decamethrin on nerve excitability was studied on the giant axons of Myxicola infundibulum. 2. Membrane resting potential was only slightly reduced; Spike amplitudes were irreversibly reduced by 8-12%. 3. Voltage-clamp analysis showed a reduction of both early transient and late steady-state conductances. Kinetic effects were a prolongation of the time to peak early transient current and a slowing down of the first component of sodium tail current. 4. These results present similarities with allethrin-treated squid axons. The mechanism of action of pyrethroids is discussed. © 1979.