THE ROLE OF THE INTRAMURAL GANGLION CELLS TAKEN IN THE ILEO-COLIC MOTILITIES OF THE CATFISH (Parasilurus asotus)

Abstract

In catfishes the role of the intramural ganglion cells taken in the ileo-colic motilities were studied. The results obtained were summarized as follows:
(1) When the stomach was half full of contents, the gastric peristalses recurrently occurred at the cardia, traveling caudad to come to an end at the pylorus.
(2) In the duodenum contractions were produced here and there, traveling both caudad and orad, to mingle the contents with each other, respectively.
(3) Along its whole length the ileum often fell in a more or less tonically contracted state, resulting in the retardation of the transfer of the duodenal contents. Furthermore, the effect described above was increased by powerful contractions which were occasionally produced here and there to travel in both directions only a short distance.
(4) When the large intestine was moderately full of contents, powerful contractions produced in the caudal half of the ileum frequently traveled caudally to expel the contents out of the anus.
(5) The supravital staining with methylene blue solution revealed that the myenteric plexus existed, whereas the submucous plexus did not contain the nerve cells. In the former, thick nerve bundles without forming meshworks took their course along the long axis of the intestine, accepting many finer axons coming from the nerve cells, which were not in groups, but lay sporadically, although they showed a tendency to increase their number in the area close to the nerve bundles. Any sign of the intrinsic mucosal reflex was not observed with the stimulation either of a spot (by rubbing with cotton) or of the whole surface (by raising the intraluminal pressure) of the mucosa of the intestine. These facts suggest that in catfishes the intramural ganglion cells have no function to regulate the strength as well as the direction of propagation of the contraction waves.