Some examples of disturbances of nerve-muscle interactions

Abstract

A disturbance of interaction between the motor nerve and muscle may have many causes. It may result from a change in the function of the motoneurone due to injury, or disease of the central nervous system. This, in turn, may lead to an altered activity pattern of the motoneurone and therefore to a considerable functional reorganization of particular motor units (see Chapter 7). In case of a disease of the motoneurone, or lesions to the motor axons, all interaction ceases and can recommence only if, and when, the damaged cell recovers, or the axon regenerates (see Chapter 6). If the neurone dies, repair can take place only by an interaction of the muscle with the nerve endings of those neurones which supply the same muscle, but are still alive. Such neurones may be induced to sprout and thus to reinnervate some of the denervated muscle fibres. Not only disease of the neurone, but also a mechanical alteration of the muscle, such as shortening for long periods of time or overstretching, may interfere with normal nerve-muscle interaction. Altering the environment of the nerve terminal due to muscle pathology can be expected to induce changes in the nerve terminals and finally their cell bodies.