Impaired muscle-nerve interaction (motility) characterizes the brachial region of dystrophic embryos.

During development ex ovo, the avian mutant with an hereditary form of muscular dystrophy demonstrates biochemical, histochemical, and physiological (functional) abnormalities which may result from impaired muscle-nerve interaction. To investigate if impaired functional activity also characterizes the dystrophic process during development in ovo, limb motility, an index of embryonic functional muscle-nerve interaction, was compared between normal and dystrophic embryos from day 6E through day 16E. A highly significant reduction in this parameter was exhibited by dystrophic wings from day 11E to day 14E inclusive. In contrast, genotypically dystrophic hind limbs demonstrated values equivalent to normal legs. Thus, in the dystrophic embryo, impaired muscle-nerve interaction characterized the brachial region exclusively during a specific period of embryogenesis.