Itonaga, M., Sunagane, N., Uruno, T. and Kubota, K. Inhibition by β-CCM of cholecys-tokinin-induced release of acetylcholine from the longitudinal muscle-myenteric plexus preparation in the guinea-pig ileum. Japanene Journal of Smooth Muscle Research, 26: 1-7, 1990. The antagonism between cholecystokinin (CCK) and methyl β-carboline-3-carbox-ylate (β-CCM) in the nervous system was studied by measuring the release of acetylcholine (ACh) from the longitudinal muscle-myenteric plexus preparation of guinea-pig. The ACh release was assessed by measuring [³H] output from the preparation preincubated with [³H] choline. Thirty mM of KCl caused a pronounced relase of [³H] ACh from the preparation. Sulfated cholecystokinin octapeptide (CCK8) also increased the release of [³H] ACh in a dose-dependent manner at concentrations ranging from 10-10M to 10^-8M. CCK8 at a concentration of 10^-8M released [³H] ACh by about 300% of the 30 mM KCl-induced [³H] ACh release. In the presence of β-CCM (10^-8M to 10^-4M), the release of [³H] ACh by KCl was not affected, but that by CCK8 was significantly inhibited depending on the concentra-tions of β-CCM. These results show that the action of CCK8 to stimulate neurons in the myenteric plexus can be selectively antagonized by β-CCM.

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Segments and Thiry-Vella type loops of the small intestine of dogs were prepared, and the excitation propagation pattern of the interdigestive migrating electric complex (IMEC) was observed by electromyography. The nerve regulatory mechanism in intestinal move-ment was investigated.
The results indicated that first, the frequency of the basic electric rhythm (BER) is controlled so that a downward gradient is formed from the upper to the lower intestine, but this gradient continues to be controlled by a two-dimensional control mechanism involving parietal factors and extrinsic nerves due to transection of the intestines and damage to the extrinsic nerves in the dominant region.
However, propagation of the IMEC in the small intestine appeared to be regulated by a combination of the two-dimensional control mechanism involving extrinsic and parietal nerves corresponding to the BER control mechanism. It was clear that the propagation mechanism of IMEC is related to the BER frequency, and propagation of the IMEC is downward in accordance with the frequency gradient of BER.

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Many workers have reported that ureteral peristaltic movement is controlled by the “so-called Pacemaker”. But, in our recent studies, it was revealed that the existence of pacemaker is not always necessary for the peristaltic movement.
In this study, we made isolated and non-isolated prototype models, using 18 mongrel dogs, to explore the influential factors on ureteral peristaltic discharge. Bilateral kidney and ureter were exposed transperitoneally. Unilateral upper urinary tract was prepared to preserve the pacemaker without renal blood supply, and contralateral one was prepared not to preserve the pacemaker by cutting at the proximal portion of the ureter.
Vesico-ureteral reflux (VUR) was caused on these two models. A luminal pressure and ureteral electromyogram was recorded.
In the result, there is spontanous peristaltic discharges of the ureter which had the tendency to increase peristaltic frequency according to the increase of the luminal pressure.
It was suggested that adequate expanding stimulation is the factor of peristaltic discharge to increase, and the peristaltic discharge under this condition propagates from upper to lower portion of the ureter.

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In order to elucidate the effects of various gastrokinetic drugs on gastric emptying and the sites of their action in the stomach, changes in gastric emptying after administration of these drugs were determined in healthy adults by means of radioisotopic technique, by setting 3 regions of interest, i. e., the whole stomach, the proximal area and the antral area.
Following results were obtained.
1. With metoclopramide administration, no particular movement of gastric contents was found for several minutes after ingestion. Once the movement of emptying was initiated, the gastric contents were transferred more efficiently from the proximal area to the antral area in comparison with the corresponding movement observed in persons given no metoclopramide. On the other hand, the outflow from the antral area to the duodenum exceeded the inflow from the proximal area to the antral area.
2. With domperidon administration, transfer of gastric contents was markedly in-creased, but the outflow from the antral area did not exceed the inflow. Domperidone caused overall facilitation of gastric emptying, mainly by enhancing the emptying movement in the proximal area.
3. With aclatonium napadisilate administration, marked transfer of the gastric con-tents from the proximal area to the antral area was noted, and the outflow from the antral area to the duodenum was equal to the inflow within 10 min, then exceeded the inflow.
4. With trimebutine maleate administration, transfer of gastric contents from the proximal area to the antral area was conspicuous, and the outflow from the antral area exceeded the increased inflow, resulting in overall facilitation of gastric emptying.

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