Retardation of symptoms of dystrophy in genetically dystrophic chickens by chemotherapy.

Chickens homozygous for muscular dystrophy were treated twice-daily with the serotonin antagonist, methysergide. Development of the dystrophic state was monitored by a test of skeletal muscle weakness, and by the characteristic marked evaluation of creatine phosphokinase (CPK) in the serum. The drug treatment prevented the onset of muscle weakness for 45 days ex ovo in all of the test animals, and for more than 60 days in 80% of them, in contrast to the untreated dystrophic animals. The CPK elevation in serum was also markedly reduced in the treated animals. A serotonin-mediated vascular effect or a direct action of serotonin on the muscle, is suggested to be involved in the development of muscle weakness in this form of dystrophy, and to be an appropriate target for chemotherapeutic control.