THE VAGAL INHIBITORY RESPONSES OF THE STOMACH TO STIMULATION OF THE DOG'S MEDULLA OBLONGATA

Abstract

The inhibition of stomach movements was investigated in the dog in which the spinal cord was previously transected. Inhibition of stomach movements was obtained through the vagus nerve by the stimulation of the medulla oblongata at 1 mm lateral to the dorsal median sulcus, 0.5-2.0 mm in depth from the dorsal surface at the level between the central alae cinerea and its oral side. On the contrary, the stimulation of the alae cinerea (dorsal nuclei of vagus) constantly produced stomach movements in the same animal in which the inhibitory response had been observed. The vagal inhibitory response was abolished by the bilateral vagotomy and also after the application of hexamethonium bromide. A large number of inhibitory areas were found in the medial longitudinal fascicle. It may be concluded from this experiment that the adrenergic nerve fibers which inhibit stomach movements are contained in the vagus nerve.