[Role of the intramural ganglion cells played in the motility of the large intestine of the tortoise, Geoclemys reevesii].
The development of the intramural plexuses in the tortoise, Geoclemys reevesii was inferior to that observed in the fowl: the meshes of both Auerbach's and Meissner's plexuses were coarser, and consisted of less number of nerve fibers. Occasionally, a small ganglion was seen at the crossing points of the meshes. The average number of nerve cells contained in the ganglion was estimated to be 1500/cm2, being about half as much as that estimated in the fowl. When the mucosa of a colon in vitro was stimulated mechanically by stroking or chemically with 1/10 N HCl, the excitability of the colonic muscle was raised at the region oral to the stimulated spot, but lowered at the region anal to it. These effects were abolished by applying a ganglion-blocking agent, hexamethonium (10(-6) g/ml), to the mucosa. When the intraluminal pressure of a colon in vitro was raised from 0 to 3-12 cm H2O, the colon was distended at first but soon contracted powerfully. The contraction became extremely reduced or was abolished when hexamethonium (3.5X10(-7) approximately 1X10(-5) g/ml) was added to the saline solution in which the colon was immersed. The results indicate that the intramural ganglion cells serve as the center of the intrinsic mucosal reflex.
D000818:Animals; D003106:Colon / Q000502:physiology; D005725:Ganglia, Autonomic / Q000166:cytology / Q000502:physiology*; D005769:Gastrointestinal Motility / Q000187:drug effects; D006584:Hexamethonium Compounds / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000502:physiology; D007420:Intestine, Large / Q000294:innervation / Q000502:physiology*; D009197:Myenteric Plexus / Q000166:cytology / Q000502:physiology; D011312:Pressure; D013368:Submucous Plexus / Q000166:cytology / Q000502:physiology; D014426:Turtles / Q000033:anatomy & histology / Q000502:physiology*
D006584:Hexamethonium Compounds