ON THE GASTRIC MOTOR RESPONSES TO THE STIMULATION OF THE CANINE PONS

Abstract

The responses of the stomach movements to the stimulation of the pons were investigated in the anesthetized and non-anesthetized dogs. The stimulated areas were determined by the histological examination.1) A hundred and fourteen motor and 78 inhibitory responses were obtained. The motor responses were obtained not only through the vagus nerves, but also through the splanchnic nerves. The inhibitory responses were obtained not only through the splanchnic nerves, but also through the vagus nerves.2) Both the motor and inhibitory effects were obtained in the same area, that is, the Formatio reticularis, Tr. vestibulospinalis, Nucl. vestibularis medialis, Tr. rubrospinalis, Fasc. longitudinalis medialis, Nucl. cuneatus, Pedunculus cerebellaris superior, Tr. spinalis n. trigemini, Lemniscus lateralis were responsible for the both reactions. Especially, the Tr. rubrospinalis and Nucl. & Tr. n. trigemini were responsible for the motor effects, and the Tr. vestibulospinalis was responsible for the inhibitory effects. The reversed responses of the stomach did not depend on the stimulating conditions or on the anesthetization or non-anesthetization of the dogs.3) The stimulation of extrapyramidal tracts, such as the Ped. cerebellaris sup., Tr. vestibulospinalis, Tr. rubrospinalis, Nucl. vestibularis lat., -inf., Fasc. longitudinalis med., Tr. tectomedullaris, Nucl. olivaris sup.caused the motor and inhibitory responses of the stomach.4) The stimulation of the cerebellar pedunculus produced both responses of the stomach.5) The stimulation of the somatic nerves and its nucleus (Nucl. motorius n. trigemini, Nucl. n. abducens, Genu n. facialis) also produced the both responses.