Exogenously applied adenosine 5'-triphosphate (ATP) caused a biphasic response;a quick relaxation followed by a slow contraction . This response was not affected by atropine, phentolamine, propranolol and tetrodotoxin .
Theophylline, quinidine and IBMX reduced ATP-induced contraction and had no effect on ATP-induced relaxation . On the other hand, apamin reduced ATP-induced relaxation and had no effect on ATP-induced contraction .
Indomethacin remarkedly reduced ATP-induced contraction without affecting the relaxation.
It was suggested that there were two types of receptors (apamin sensitive and apamin resistant) in the guinea-pig gallbladder .

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We studied isolated bovine mesenteric lymphatics to investigate the pharmacological properties of the postjunctional-adrenoceptors. Rings of the lymph vessels were mounted for isometric tension recording in organ chambers filled with Krebs-Ringer bicarbonate solution . The lymph vessels contracted when exposed to phenylephrine and clonidine. The relative sensitivity of the vessels to clonidine was larger than to phenylephrine. Yohimbine was a competitive antagonist against phenylephrine and clonidine in the lymph vessels. Prazosin caused a parallel shift to the right of the dose-response curve to phenylephrine, and not to clonidine in the vessels. The Schild's plot for yohimbine in the lymph vessels suggests that the presence of both alpha 1-and alpha 2-like adrenoceptors on lymphatic smooth muscle cells.

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Studies were conducted in three conscious dogs implanted with electrodes and force transducers on the gastric antrum and duodenum.
1. During the period of development of the interdigestive myoelectric complex (IMC) or the interdigestive contractions, intervals of development and amplitudes of the basic electric rhythm (BER) in the antrum varied markedly in contrast with those during the period of motor quiescence. In the antrum and duodenum, the frequency of BER decreased during IMC, and transiently increased after the end of IMC.
2. After feeding, action potentials were superimposed on every BER of the antrum which occurred regularily, and a contraction accompanied each group of action potentials. While, in the duodenum, the percentage of BER's with action potentials was about 40%. The frequency of BER decreased in the antrum and increased in the duodenum compared with that before feeding. Wave form of action potentials and/or amplitude of contractions varied and the maximum amplitude of the contractions in the digestive state never exceeded that of the interdigestive contractions .
3. Ratio of BER frequency of the duodenum to that of the antrum was 3.7-4.4 during the motor quiescence, while, during the period of development of the interdigestive contractions and the contractions in fed state, it was relatively high (4.3-4.6).
4. Coinciding with the strong contractions among the interdigestive contractions of the antrum, diminution of the high-amplitude contractions in the duodenum was observed. On the other hand, in the digestive state, cyclic occurrence of a contraction in the antrum approximately corresponded in time with occurrence of contractions in the duodenum.

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Responses of the gastric antrum and duodenum to some drugs were studies in fasted state of conscious dogs using implanted force transducerr and/or electrodes.
1. Continuous i.v. infusion of pentagastrin (12-30 μg/kg-hr), secretin (1.8 u/kg-hr) and atropine (30-120 μg/kg-hr) suppressed the development of the interdigestive myoelectric complex or the interdigestive contractions.
2. During infusion of atropine or secretin, action potentials superimposed on basic electric rhythm (BER) and contractions were frequently observed in the duodenum in spite of motor quiescence in the antrum. A bolus i.v. injection of bethanechol (10-20 μg/kg) clearly produced action potentials and contractions in the duodenum, while, in the antrum, only a few contractions were observed. Pentagastrin (12-30 μg/kg-hr, 5-10 μg/kg i.v.) induced weak but high-frequency contractions in the antrum, whereas, in the duodenum, contractions were scarecely observed except the case of the infusion of the drug over 30 min. The drug also changed the frequency and amplitude of BER remarkably in both regions.
3. Phentolamine (3.0-6.0mg/kg-hr, 1.0-1.5mg/kg i.v.) introduced strong contractions similar to the interdigestive contractions. The result indicates that diminution of the adrenergic nerve activity of the myenteric plexus is one of the factors participating in occurrence of the interdigestive contractions.

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Intraluminal manometric and cine-cholangiomanometric studies were carried out on the movement of the sphincter of Oddi at the time of excretion of bile into the duodenum in 12 patients after cholecystectomy for gallstone.
Two phases were observed in the sphincteric movement ; the resting phase without any contraction and active phase with vigorous contraction.
On stimulation with CCK-PZ 0.5u/kg (bolus injection) in a active phase, a prompt transition from the active phase to the resting phase was observed in 4 to 8 minutes.
On cine-cholangiomanometric study, the contrast medium injected into the common bile duct did not flow into the duodenum at the resting phase, but in the active phase. In the active phase, the excretion of the contrast medium was observed at the end of each contraction of the sphincter of Oddi.
These observations have led a conclusion that bile excretion occurs in the active phase of the sphincter of Oddi in the cholecystectomized patients.

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Effect of oxatomide on contraction of canine bronchial smooth muscle caused by administration of histamine and by challenge of ascaris-antigen were investigated and compared against the effects of histamine H₁-receptor antagonist (CPM) and inhibitor of histamine release from mast cells (DSCG).
Oxatomide in concentrations of 0.05μg/ml to 2.0μg/ml inhibited, dose-respon-sively, contraction of bronchial smooth muscle strip by administration of histamine (10μg/ml). When this concentration was less than 0.3μg/ml, CPM inhibited the contraction significantly stronger than oxatomide. However, in concentration over 0.5μg/ml, no difference in inhibitory effect could be demonstrated. On the other hand, DSCG could not inhibit the contraction. Oxatomide in concentrations of 0.05μg/ml to 1.0μg/ml inhibited, dose-responsively, contraction of the muscle strip sensitized spontaneously by ascaris antigen challengs. There was no difference in inhibitory effect between oxatomide and DSCG at the same level of concentration. Oxatomide (0.5μg/ml) and CPM (0.5μg/ml) both inhibited completely the constriction response of bronchus caused by histamine stimulation (10μg/ml). Although constriction response by ascaris antigen challenge was inhibited completely by oxatomide (0.5μg/ml), it could not be inhibited completely by CPM (0.5μg/ml). Oxatomide inhibited even the residual constriction response which could not accomplished by CPM.
These results suggest that oxatomide might have not only an effect as a histamine H₁-receptor antagonist and anti-histamine releasing agent from mast cell, but also anti-SRS-A.

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