Takehiko Semba

EFFECTS OF PHYSOSTIGMINE AND DUVADILAN ON AN ATROPINE-RESISTANT CONTRACTION OF DOG'S STOMACH

Effects of atropine, physostigmine, duvadilan and tetrodotoxin on the mechanical activity of the longitudinal muscle preparation of dogs 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.

AN ATROPINE-RESISTANT CONTRACTION OF DOG'S STOMACH IN RESPONSE TO STIMULATION OF THE VAGUS AND SPLANCHNIC NERVES

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.