Pathologic effect of phencylidine and restraint on rat skeletal muscle structure: Prevention by prior denervation

Extensive disruptions of myofibrillar architecture or extensive areas of Z-band smearing occur in less than 2% of skeletal muscle fibers of the vastus lateralis muscle of untreated male Sprague-Dawley rats. Restraint for 2 hr, a potent stress in the rat, did not significantly increase the occurrence of extensive myofibrillar disruption, and acute or chronic administration of the potent psychotomimetic-anesthetic, phencyclidine, had only a slight effect on rat skeletal muscle morphology. However, phencyclidine plus restraint resulted in the occurrence of extensive areas of myofibrillar disruption and extensive Z-band smearing as well as scattered, segmental necrosis. Denervation of quadriceps femoris 40-48 hr prior to phencyclidine and restraint almost completely blocked the occurrence of any lesions. This suggests that intense muscle activity, with increased demand for and utilization of oxygen, can produce extensive architectural changes in skeletal muscle.