Anode break excitation in denervated rat skeletal muscle fibres.

1. Anodal break action potentials were found to be a feature of denervated rat skeletal muscle fibres.2. Depolarized innervated fibres failed to respond to anodal break stimulation in the same way as denervated fibres.3. The critical level for action potential generation is related to membrane polarization in denervated fibres but not in innervated fibres. This relationship is inhibited by the I.P. administration of actinomycin D, which also prevents the onset of anodal break action potentials in 3-day denervated fibres.