Nifedipine acts on smooth muscle cells to prevent the influx of calcium ions. The present study was undertaken to see wheather a relaxatory effect of nifedipine is present on esophageal smooth muscle as well as on vascular smooth muscle. The experiment was performed on anesthetized dog's lower esophageal sphincter pressure (LESP). Nifedipine (0.5 mg/kg) administered sublingually caused rapid and marked depression of LESP. LESP response to either AOC-tetragastrin (0.5μg/kg) or bethane-chol (5μg/kg) was inhibited partially but markedly. This inhibition might be caused by prevention of calcium-ion influx. This depressant effect of nifedipine on LESP both in resting state and in stimulated state is able to apply to therapy of hypermotile disorders of the esophagus.

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NIWA, A., MIYAZATO, T., MURAKAMI, N. and SUZUKI, A. Effects of Cadmium on the Isolated Vas Deferens from Guinea Pig. Japanese J. Smooth Muscle Res., 1981, 17, (2), 53-58-The effects of cadmium on the responses to the agonists, K, acetylcholine, noradrenaline, Ba and Ca were investigated in the isolated was deferens from guinea pig.
1. The low concentration of cadmium enhanced the effects of tested agonists, and the enhancement was larger in order of K, Ba, Ca, noradrenaline=acetylcholine.
2. The high concentration of cadmium inhibited the effects of tested agonists with a dose-dependent manner. The inhibitory effect was weaker against the contraction by K and was stronger against the contractions by Ba, Ca, acetylcholine and noradrenaline.
3. The inhibitory effects of cadmium against the contractions by acetylcholine and noradrenaline were almost the same.
4. On the shape of contraction by K, cadmium showed the stronger inhibition against the tonic contraction than the phasic contraction.
5. The above mentioned results were mainly discussed on the Ca mobilization and the receptor selectivity.-Vas deferens, Cadmium, Ca, K, Acetylcholine, Noradrenaline, Ba

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During selective proximal vagotomy (SPV), atypical SPV (atyp-SPV) was proposed when either the anterior or posterior nerve of Latarjet was sacrified.
In order to study the gastric motility after atyp-SPV, eight mongrel dogs on which SPV had been performed underwent atyp-SPV, with subsequent transthoracic truncal vagotomy (TV). These surgeries were performed at about 4 to 5 week intervals, and gastric myoelectrical activities were recorded serially through chronically implanted four bipolar electrods in the stomach.
In another four dogs with atyp-SPV, contractile activities of the gastric wall were recorded by means of waterproof strainguages sutured on the gastric wall.
Following atyp-SPV, the mean propagation velocity and discharge interval of the stomach were approximately similar to those in SPV, except for slightly decreased propagation velocity and slightly prolonged discharge intervals in only the early postprandial period after transection of the posterior nerve of Latarjet.
Subsequent TV decreased the propagation velocity significantly although it did not alter the discharge intervals except in the early postprandial period.
Atyp-SPV maintained gastric contraction with a waxing and waning pattern of varying amplitudes in the antrum and monotonic activities in the corpus.
These results substantiate that atyp-SPV keeps gastric motility similar to SPV and can be performed as an alternate modality of SPV, when necessary.

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The authors have suggested from an in vitro study that extracellular K concentra-tion can be elevated up to 40 mM, when hemolysis of a clot occurs after subarachnoid hemorrhage. The present experiments were performed to investigate the change in contractility of rabbit basilar artery to vasoactive substances in the presence of increased K. The conclusion was as follows.
1. The contraction heights induced by serotonin (5×10^-7M) were increased 2.4±0.2 fold, 6.4±0.3 fold, 5.7±0.4 fold (n=10), when the K concentration of physiological solution was elevated to 8.1 mM, 13.5 mM, 24.3 mM, respectively.
2. Similar potentiation was obtained in prostaglandin F_2α. The tensions induced by prostaglandin F_2α (2.5×10^-6M) were increased 2.3±0.3 fold, 4.7±0.4 fold, 3.7±0.4 fold (n=6), whereas the responses to norepinephrine were rather less potentiated and the maximum height was 2.2±0.2 fold (n=8) in 13.5 mM K.
3. Enhancement of the responses to vasoactive agents was also observed in the presence of tetraethylammonium (TEA).
These results indicated that slight deporalization of membrane would potentiate the contractile responses to various vasoactive substances and that an increase in sensitivity could be a possible cause of cerebral vasospasm.

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