Motor response of the stomach and small intestine caused by stimulation of the peripheral end of the splanchnic nerve, thoracic sympathetic trunk and spinal roots.

Various discussions have been made by many investigators on the motor effect produced by stimulation of the splanchnic nerve which has been almost universally noted to be the inhibitory nerve to the stomach and small intestine (Kuntz1953, Hukuhara1953). Many workers have speculated as to whether or not the intensity, frequency and type of stimulation (Brown, McSwiney and Wadge1930, Barry1932, Hukuhara et al. 1954, Semba et al. 1955), the kind of anesthesia (Brown and McSwiney1932, Hukuhara et al. 1954), the activity and inactivity of the wall of the alimentary tract ( Vearch1925, Brown and McSwiney 1926, McCrea and McSwiney1928), its blood flow (Vearch1925, McCrea and McSwiney1928, Hukuhara et al. 1954) and so on, have any correlation to the production of a reverse effect of splanchnic stimulation. However, absolute conditions capable of producing reversal of splanchnic action could not be determined on the side of the gastro-intestinal tract or on the side of the stimulus. On the other hand, from the experiment on the motor reflex from the urinarybladder to the stomach and small intestine and from the experiment of gastrointestinal motor response which can be produced by central stimulation of the pelvic nerve, we were able to confirm that one of the motor efferent pathways was contained in the splanchnic nerve (Semba et al. 1956a). These experiments suggest to us that the motor effect is produced by the action of functionally different fibers from the inhibitory nerve in the splanchnic nerves. The present study was undertaken to obtain the absolute conditions necessary to produce motor effect of the stomach and small intestine of both dogs and toads by the stimulation of the splanchnic nerve, thoracic sympathetic trunk and spinal roots.