Polarity of effects of stimulation of Auerbach's plexus on longitudinal muscle.

The effects of repetitive electrical stimulation of nodes in Auerbach's plexus on the longitudinal muscle of rabbit intestine were investigated. Peeled longitudinal muscle strips, with adherent Auerbach's plexus, were obtained and placed under a stereodissecting microscope. Neural elements within nodes of Auerbach's plexus were stimulated repetitively using a metal microelectrode with tip diameter of 5 micrometer. Stimuli applied to a node generally caused excitation of the longitudinal muscle on the oral side and inhibition on the anal side of the point of stimulation. Excitation of the muscle was mainly cholinergic, and inhibition of the muscle was nonadrenergic. From the results of the present study the concept of the law of the intestine, excitation above and inhibition below the stimulated spot, was supported.