Effect of colchicine on the electrophysiological properties of the toad sciatic-gastrocnemius preparations in vivo.
The effects of a single subepineural injection of colchicine on the toad sciatic-gastrocnemius preparation were studied in vivo. The resting membrane potential of the gastrocnemius muscle fibres declined by 15% at day 5. This was followed 2 days later by dispersion and reduction in the amplitude of the compound muscle action potential, decrease in the slope of the accommodation index curve (AI), and a decreased electromyographic interference pattern. These changes were progressive and led to blockage of electrical activity and appearance of pseudodenervation after 2 weeks. Pseudodenervation was confirmed on finding similar alterations in the AI profile in neurotomized toads. In contrast, the hind limbs of toads paralysed by d-tubocurarine had normal muscle AI. The decrease in the AI on the colchicine-treated side was dependent on the length of the severed nerve left attached to the muscle, indicating a centrifugal effect of the drug.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001001:Anura; D003078:Colchicine / Q000494:pharmacology*; D004576:Electromyography; D004594:Electrophysiology; D008564:Membrane Potentials / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects*; D012584:Sciatic Nerve / Q000187:drug effects; D014403:Tubocurarine / Q000494:pharmacology
D003078:Colchicine; D014403:Tubocurarine