"RED" SKELETAL MUSCLE FIBERS: RELATIVE INDEPENDENCE OF NEURAL CONTROL.

Studies on skeletal muscle of rats and mice indicate significant differences between the behaviors of the two basic types of muscle fibers during the development of denervation atrophy. While the diameter of fibers possessing sarcoplasmic granularity ("red" fibers) is preserved for a long time after complete severance of motor and sensory nerves, fiber with agranular cytoplasm ("white" fibers) undergo rapid atrophy. It is concluded that, at least in this respect, the "white" fibers are more dependent on neural control than are the "red" fibers.