Influence of isaxonine on reinnervation of the rat gastrocnemius muscle.

Isaxonine is reported to have a favourable effect on nerve regeneration. The histological and histochemical changes were compared in the gastrocnemius muscles of 20 rats, in which the left sciatic nerve was frozen-crushed for 10 s at the level of the buttock. The animals received a daily dose of intraperitoneal isaxonine and ten others the solvent only. After 8 weeks small type grouping was seen in rats receiving solvent only and large type grouping in rats treated with isaxonine. After 10 weeks a checkerboard pattern of the fibre types was observed in the muscles of animals receiving solvent only but fibre type grouping was present in those treated with isaxonine. This experiment indicates that isaxonine prevents synaptic remodelling by suppression of the redundant nerve endings from additional axons, which have regenerated more slowly, in making contact with motor endplates.