ON SPLANCHNIC MOTOR RESPONSES OF STOMACH MOVEMENTS PRODUCED BY STIMULATION OF THE MEDULLA OBLONGATA AND SPINAL CORD

Abstract

The medulla oblongata and the cervical and thoracic cord of dog were stimulated by electrodes of 20, 30 and 52 /n in diameter, and the vagal and splanchnic motor effects of the stomach were observed. The stimulated positions were examined histologically and the following results were obtained: Motor response of the stomach was obtained through both the vagal and the splanchnic nerves by stimulation. The areas which produced the vagal motor effect were found in the area of nucleus alae cinerea. They occupy the whole length of the alae cinerea from the oral part of calva on the dorsal surface of medulla. The areas which produced the splanchnic motor effect were also located in the area of nucleus alae cinerea, extending to the grey substance of the spinal cord. They occupy the lower part of the alae cinerea on the dorsal surface of medulla. Therefore, it may be concluded that both the vagal and splanchnic motor areas to the stomach have the same origin in the medulla oblongata, i.e. nucleus alae cinerea. It extends, on the one hand, toward the oral side of the vagus nerves, and on the other hand, it extends caudally through the cervical and thoracic cord and via the dorsal root to the splanchnic nerves.