Effects of denervation on the ultrastructure of insect muscle

Abstract

ABSTRACT The structure of normal and denervated muscle fibres in the metathoracic retractor unguis muscle of the locust (Schistocerca gregaria) has been examined. Section of the 2 motor neurons which innervate this muscle results initially in muscle hypertrophy but this is followed about 4 days post neurotomy by progressive atrophy. Atrophy of the retractor unguis muscle is characterized by a decrease in muscle volume and degeneration of muscle organelles, e.g. mitochondria, sarcoplasmic reticulum, transverse tubular system, protein filaments, etc. During its later stages the degeneration of the denervated muscle is possibly assisted by the phagocytic action of haemocytes which invade the muscle.