An electromyographical study of the intestinal movement in simple obstruction was performed in dogs and the conclusions are as follows.
1. When the intestinal tract was obstructed by a ligation apparatus, electromyographically spike waves disappeared reflectively in both upper and lower intestinal tracts in the ligation site, and the resting pattern showing only BER was maintained for 20 to 80 minutes.
2. The spike waves which reappeared were blocked at the ligation site without conduction from upper part to lower part.
3. A comparison of electric activities after obstruction shows that at the upper part activities started to increase earlier and then gradually decreased 5 hours after obstruction. Activities at the lower part, on the contrary, started to decline immediately and this declining tendency continued for long time.
4. Abnormal propagation patterns appeared about 3 hours after obstruction and were observed at both the upper and lower parts of the ligation site.
5. The propagation-velocity increased linearly for 7 hours after obstruction in the upper part and finally reach a plateau. At the lower part the velocity was nearly fixed at the control level.
6. A comparison of BER frequency after obstruction shows that at the lower part of the ligation site the frequency decreased remarkably in an earlier period, while in the upper part it became prominent for 24 to 30 hours.

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This study was intended to specify the most appropriate procedure of myotomy and fundoplication in the modified Belsey Mark IV operation toward the esophageal achalasia to prevent post-operative refluxes.
Adult mongrel dogs were prepared under surgical operation of
1) short myotomy, short fundoplication
2) long myotomy, long fundoplication
3) long myotomy, long fundoplication of artificial hiatus hernia type
4) control.
After the well recovery, they were examined on their simultaneous evaluation of pH and inner pressure at three points, i.e. the esophagus, the high pressure zone (HPZ), and the stomach. At the same time, withdrawal pH curves, etc. were also determined.
The discussion resulted that the group of short myotomy, short fundoplication and the group of artificial hiatus hernia type long myotomy, long fundoplication were significantly superior to the group of long myotomy, long fundoplication.
As the consequence of the experiment, firstly, the possibility that the surgical operation of long myotomy, long fundoplication causes hypertension of the intrathoracic esophagus, which resulted in the dysfunction of the anti-reflux mechanism of the valves was suggested. Secondly, it has been revealed that this dysfunction did not occur in the surgical operations on the length of HPZ. And thirdly, when the conventional Mark IV operation, which buries all the portions of the fundoplication under the diaphragm, causes hypertension to the intrathoracic esophagus, the surgical operation of artificial hiatus hernia type shall be applied to herniate the upper portion of the fundoplication to the thoracic cavity.

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The lower esophageal sphincter (LES) is observed as a zone with higher esophageal pressure by manometric studies and considered to save a barrier against gastric pressure.Mechanisms to prevent GER have still not been fully understood.
Manometric studies and pH studies were performed in dogs and in infants. The following results were obtained:
1. Experimental studies
Increasing gastric pressure with 0.1N HCl, LES relaxation was elicited by increased esophageal pressure after GER was detected by pH measurment. LES pressure increased with increased abdominal pressure and decreased with elevated intraesophageal pressure after intraluminal injection of normal saline. Inflation of the esophagus with air caused GER when gastric pressure elevated with 0.1N HCl.
2. Clinical studies
Manometric studies were performed in 63 infants with or without GER. Infants with GER had higher esophageal pressure, lower LES pressure and shorter LES than infants without GER (p<0.001).
In conclusion, these studies may indicate that relaxation of LES caused by increased intraesophageal pressure induces GER in infants.

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Using adult mongrel dogs, gastroduodenal motility, gastric emptying and pertinent serum motilin levels were measured under concious states before and after transthoracic truncal vagotomy. Gastroduodenal motility was recorded by chronically planted strain gage transducers along the gastrointestinal tract. Gastric emptyings were measured by x-ray examinations after barium-meat-meal ingestions or by gastric contents sampling method through the total pouch cannula after normal dog food ingestions. Results were as follows;
1. Gastric motility patterns recorded by strain gage transducers were classified into two patterns that were a digestive pattern (D.P.) and an interdigestive pattern (I.P.). Serum motilin levels were elevated during high-amplitude contractions and lowered during resting phase of interdigestive periods.
2. After vagotomy, strengs (hights) of antral contractions and phasic changes were decreased with the lack of I.P. These postvagotomy changes were thought to be related with the delayed gastric emtying after vagotomy. Gastric lavation through the cannula or pyloroplasty produced no effect on recovery of I.P. This fact suggested that the lack of I.P. was the direct effect of vagotomy and not due to delayed gastric contents emptying.
3. On the assumption that motilin had the major role on the regulation of I.P., vagotomy seemed to produce an effect to prevent phasic motilin release.

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This study was intended to elucidate possible temporal changes of the valve and fundoplication which are formed by modified Mark IV operation as a surgical treat-ment of esophageal achalasia. Heller's procedure was also studied in terms of its comparison with the above operation.
Adult mongrel dogs were operated on as follows and studied at the following postoperative points:
1) Heller's procedure … at the forth postoperative week
2) Modified Mark IV operation…at the forth postoperative week
3) Modified Mark IV operation…at the third postoperative month
Postoperative comprative studies were made on temporal changes of the anti-reflux effect by intraesophagogastric pressure and withdrawal pH examinations, measurements of intragastric pressure at reflux through simultaneous evaluation of intraesophageal pH and inner pressures at 3 points, i.e. the esophagus, the high pressure zone and the stomach, and histological and morphological examination.
From the above the following conclusion was drawn: The valve formed by modified Mark IV operation showed temporally a shortening tendency, and a signifi-cant shortening of the length of valve was observed also in comparisons of values between the forth postoperative week and the third postoperative month. Also in terms of the measurement of inner pressures, a significant decrease was observed in the length and the force of high pressure zone.
However, comparisons of the intragastric pressure values at reflux revealed no significant difference in values between the forth week and the third month after the modified Mark IV operation and almost similar anti-reflux effects between both in spite of a shortening of the valve. The above results suggested that more reliable and long-term sustaing of the anti-reflux effect needed more extensive formation of the fundoplication.

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Adult cats were used under sodium pentobarbital anesthesia in order to investigate static and dynamic responses of mechanoreceptors within gastric wall to intragastric pressure changes caused by air inflation of the stomach.
By means of tungsten microelectrodes, 17 afferent activities in response to gastric inflation were recorded from cervical vagal nerve trunk.
Two modes of gastric inflation were applied (a) intermittent type for studying static response and (b) staircase one for studying dynamic response.
The following results were obtained:
1. Static response: An exponential relation was observed between intragastric pressure and frequency of gastric afferent activity, so maximal estimated frequency (f_max) and pressure constant could be calculated using method of extrapolation and method of least squares. Pressure constant is defined as an intragastric pressure at which frequency response is about 63% of f_max. Only one peak was seen in histogram of pressure constants of 17 afferent activites. Their average mean was 24±3cmH₂O.
2. Dynamic response: A linear relation was observed between dynamic index and rate of pressure change.
Dynamic index is defined as the net increment of frequency on dynamic phase of gastric inflation obtained by the difference between the maximal frequency and the frequency at three seconds after dynamic inflation.
Dynamic constant which is considered to indicate the sensitivity of the receptor is defined by the slope of the regression line of dynamic index and rate of pressure change.
Histogram of dynamic constant revealed two peaks, the large one with a mean of 10.2±4.0imp/S/cmH₂O/S and the small one with a mean of 2.5±0.5imp/S/cmH2O/S.

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In order to clarify the gastric motility after segmental gastrectomy (SG) with selective proximal vagotomy (SPV), seventeen canines equipped with four bipolar electrodes on the anterior wall of the stomach underwent four types of operation:
1-group, SG (middle corpus) with SPV-6 dogs;
2-group, SG (middle corpus) with SPV and pyloroplasty-5 dogs;
3-group, SG (upper corpus) with SPV-3 dogs;
4-group, SG (middle corpus) with antral vagotomy (AV)-3 dogs.
1-group: In the preanastomosis, the basic electrical rhythm (BER) frequency was not altered significantly, but the propagation velocity of the BER decreased by about 2 to 20% in the late postoperative period.
In the postanastomosis, the BER frequency was markedly reduced, but progres-sively recovered to show the synchronization with that in the preanastomosis following 15 to 30 days postoperation. The propagation velocity of the BER decreased by about 3 to 25% in the late postoperative period.
In the postanastomosis, dysrhythmias were observed to occur in high incidence in the early postoperative period, but were transient occurence.
2-group: The high-frequency-dysrhythmias (about 10 cycles/min) were observed. Pyloroplasty increased the frequency of dysrhythmias due to deranging the electric insulator of the pyloric ring.
3-group: In the late postoperative period, the BER frequency didn't synchronize with that in the preanastomosis in fasting.
4-group: Dysrhythmias were observed to occur in the late postoperative period.
It was suggested that the gastric motility of the SG with SPV recovered in the late postoperative period, therefore pyloric ring can be preserved.

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Ueda, F., Kishimoto, T., Karaki, H. and Urakawa, N. High K-induced Contraction in Rabbit and Monkey Tracheal Smooth Muscle. Jap.J. Smooth Muscle Res., 1983, 19 (6), 541-549. - High K-induced contractions in rabbit and monkey tracheal smooth muscle were characterized. A substituted 60mM K, 94.1mM Na solution produced a sustained contraction in both preparations. The 60 mM K-induced contraction in rabbit trachea was inhibited by Ca removal, verapamil, glucose-removal and hypoxia but not by sodium nitroprusside. The 60mM K-induced contraction in monkey trachea was inhibited by Ca removal, verapamil, sodium nitroprusside and hypoxia but not by glucose-removal. In rabbit trachea a substituted 154.1mMK, Na deficient solution induced a rapid rise in tension followed by a gradual decrease. Wet weight of rabbit trachea increased in the 154.1mM K solution. Both the decrease in the developed tension and the increase in the wet weight were prevented by the hyperosmotic addition of sucrose (50-100mM). The decrease in the developed tenison was also partially antagonized by the addition of pyruvate or oxalacetate. In monkey trachea, the sustained contraction induced by the 154.1mM K solution showed very slow decrease following the increase in the wet weight of the tissue. The decrease in muscle tension was prevented by the addition of hyperosmotic sucrose. These results suggest that, in rabbit tracheal smooth muscle, the decrease in the developed tension in isosmotically substituted high K, N a deficient solution may be attributable mainly to the swelling of muscle cells and partly to the inhibition of glucose utilization resulting from Na deficiency. In contrast, the contraction in monkey trachea seems to be inhibited, although slightly, by the swelling of the cells.

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