[Excitability of spinal cord motor neurons and effect of stimulating peritoneal receptors]

The change of reflex motoneuron excitability of sacral spinal cord segments was investigated by method of monosynaptic testing in acute experiments on spinal dogs. The H- and M-responses of square plantar muscle were recorded. The presence of H1- and H2-components of monosynaptic nature was revealed in this muscle. Chemical irritation of abdominal viscera led mostly to a decrease of H-response threshold, an increase of its maximal amplitude and growth of post-tetanic potentiation effect. The latter change was more obvious for H2-component. The data obtained suggest an increase of reflex excitability of both "fast" and "slow" spinal motoneurons on intensive irritation of peritoneum.