Role of Peripheral Inhibition in the Control of Arthropod Muscle

Abstract

Peripheral inhibition, i.e., the suppression of excitatory phenomena of effector organs by the action of inhibitory nerve fibers, is a feature common to many animal phyla including vertebrates, mollusks, and arthropods. In the vertebrates, peripheral inhibition is restricted to the action of neurons belonging to the autonomic division of the nervous system; in mollusks, as far as is known at the present time, peripheral inhibition is restricted to the heart and the gut. In arthropods, however, inhibition involves also—and predominantly—the skeletal muscles, and inhibitory neurons are part of the regular efferent innervation of striated skeletal muscle. This was first recognized by Biedermann in 1888 and later confirmed by Mangold (1905) and Hoffmann (1914), working on crayfish. Since then some alternative hypotheses have been proposed which explain inhibitory effects of nerves on muscles in a different way, ascribing the inhibition of contraction to an effect of the motorneurons (MNs) themselves (“overexcitation,” “Wedensky inhibition”: Fröhlich, 1907; Fraenkel-Conrat, 1933; Segaar, 1929).