Morphometric effects of use and disuse on peripheral nerve

C. S. Calder and M. Pollock

Rat peripheral nerve was evaluated morphometrically following hemicordotomy, tenectomy, or both to assess the effects of disuse and hyperactivity on the peripheral nervous system. Hemicordotomy resulted in an increase in diameter of nerve fibers supplying both "fast" and "slow" skeletal muscles in hypoactive and hyperactive limbs. Nerve fiber atrophy occurred only in nerve to "fast" muscle following disuse induced by hemicordotomy and tenectomy. The possible role of "motor nerve growth factor" or altered axoplasmic flow in bringing about these morphologic changes in peripheral nerve is discussed.