Search

Effects of atropine, physostigmine, duvadilan and tetrodotoxin on the mechanical activity of the longitudinal muscle preparation of dog's stomach in vitro experiments and on the motility of stomach in the same animal in vivo experiments were investigated. 1. The latency of an atropine-resistant contraction which was produced by stimulation of vagus nerve was increased in period in accordance with the augmentation of concentration of atropine in vitro experiments. 2. Physostigmine reconstructed the atropine-resistant contraction which was abolished by duvadilan as well as the cholinergic contraction which was abolished by atropine in vivo experiments. 3. Duvadilan abolished the cholinergic and atropine-resistant contractions in vitro, but in vivo experiments duvadilan abolished only the atropine-resistant contraction. 4. An atropine-resistant contraction was completely abolished by administration of tetrodotoxin. But the direct electrical stimulation of the muscle caused the contraction of it which was blocked by tetrodotoxin.

1. A study was made in vivo experiments of a contraction of stomach of the dog to stimulation of the extrinsic nerves, medulla oblongata and thoracic cord in the presence of atropine. 2. An atropine-resistant contraction of stomach was produced without accompanying any preceding relaxation of stomach motility. It seems to deny that an atropine-resistant contraction appears to be a rebound phenomenon. 3. An atropine-resistant contraction was produced in prolonged stimulation. A delay of latency to produce a contraction of stomach was more than 27 sec and a contraction was decreased in amplitude and frequency in the presence of atropine.

In experiments on dogs the influences of peristaltic contraction of the distal colon on blood flow through the colonic vein were studied. Blood flow was recorded continuously by electro-magnetic flow-meter.The peristaltic contraction of the distal colon caused the periodicity on the flow-meter tracing of the colonic vein.Three groups of the correlation between the peristaltic contraction and venous blood flow were observed. The first pattern is that the abrupt augmentation of the colonic blood flow was elicited during the contraction. The second pattern is that the diminution of colonic blood flow during the contractile phase was followed by the sustaining augmentation of the blood flow during the relaxation. The above mentioned two patterns being in combination is the third pattern. That is, the augmentation of the blood flow during the contraction was followed by the diminution of blood flow corresponding to the highest level of contraction and by the sustaining augmentation of blood flow during the relaxation. The third type was usually elicited by the stimulation of the pelvic nerve.The initial augmentation of blood flow is due to propulsive action on the blood within the colonic vessels. The secondary augmentation of blood flow is depended on the vascular dilatation which is caused by the obstruction of blood flow through the colon during the prolonged contraction.