Japanese Journal of Smooth Muscle Research
Online ISSN : 1884-8788
Print ISSN : 0374-3527
ISSN-L : 0374-3527
Volume 22, Issue 5
Displaying 1-6 of 6 articles from this issue
  • [in Japanese]
    1986 Volume 22 Issue 5 Pages 375-407
    Published: October 24, 1986
    Released on J-STAGE: July 21, 2010
    JOURNAL FREE ACCESS
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  • Tomoko SHIMADA, Akio Tsuji, Keiichi SHIMAMURA, Satoru SUNANO
    1986 Volume 22 Issue 5 Pages 409-422
    Published: October 24, 1986
    Released on J-STAGE: July 21, 2010
    JOURNAL FREE ACCESS
    Shimada, T., Tsuji, A., Shimamura, K. and Sunano, S. Comparison of contractile effects of sodium vanadate and ouabain in vascular smooth muscle of guinea-pig and rats. Japanese Journal of Smooth Muscle Research, 1986, 22 (5); 409-422- Ouabain and vanadate are known as potent inhibitors of Na, K-ATPase in various tissues including smooth muscles. Both agents showed contractile action on various smooth muscles in a similar fashion: stronger contractile action on the aortae of rats (WKY and stroke prone spontaneously hypertensive rats, SHRSP) and guinea-pigs, and weaker contractile actions on basilar and mesenteric arteries of the same animals. Time to peak tension, however, was far longer in ouabain-induced contraction. Phentolamine depressed ouabain-induced contractions, while vanadate-induced contractions were not affected. Elevation of K+ concentration to 20 or 30 mM potentiated vanadate-induced contraction markely, while it potentiated ouabain-induced contraction only slightly. DIDS blocked vanadate-induced contraction but showed no effect on ouabain-induced contraction. Removal of Ca abolished ouabain-induced contractions, while vanadate-induced contractions of reduced height could be observed in the absence of Ca. Verapamil depressed both ouabain-and vanadate-induced contractions of WKY and SHRSP aorte aut exhibited no effect on the guinea-pig aorta. Thus, although similarities of the action of ouabain and sodium vanadate were observed, the modes of the actions were revealed to be different in the two agents. Inhibition of Na, K-ATPase might be involved in the case of ouabain-induced contractions, and inhibition of Ca-ATPase of membranous systems might be involved in vanadate-induced contraction.
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  • Nagao SUZUKI, Cornelis van BREEMEN
    1986 Volume 22 Issue 5 Pages 423-436
    Published: October 24, 1986
    Released on J-STAGE: July 21, 2010
    JOURNAL FREE ACCESS
    Suzuki, N. and van Breemen, C. The role of membrane depolarization in norepinephrine-induced contractions of the rabbit mesenteric resistance artey. Japanese Journal of Smooth Muscle Research, 1986, 22 (5): 423-436 Changes in membrane potential during norepinephrine-induced contractions in the rabbit mesenteric resistance artery (3rd or 4th branch) were investigated using microelectrodes. Norepinephrine at concentrations greater than 10-6 M depolarized the membrane and induced contractions dose-dependently. Maximum effects were produced by 10-4 M norepinephrine. Depolarization was maintained at almost steady level during 15 Min application of norepinephrine. During the same period, contractions continued with slight decay. Oscillatory contractions were observed at more than 3×10-6 M norepinephrine, and occasionally persisted throughout the application of norepinephrine. Treatments with Ca2+-rich 1 mM EGTA solution, 10-5 M diltiazem, 3×10-6 M D600 and 1 mM La3+ did not significantly affect the amount of depolarization induced by 10-4 M norepinephrine; however, contractions were greatly inhibited by these treatments. Replacement of Na+ by choline markedly reduced depolarization while contractions were not affected. In Ca2+-free Na+-free solution, no depolarization was induced, while contractions were still produced by norepinephrine, indicating that Cl- was not essential for membrane depolarization. These results suggest that contractions of the rabbit mesenteric resistance artery to norepinephrine are mainly due to the enhanced influx of extracellular Ca2+ which is not dependent on potential-sensitive mechanisms. Depolarization is thought to be due to the increase in the membrane permeability to Na+ and Cl- which is coincidentally produced by norepinephrine. The membrane potential oscillations were dependent on Ca entry but could not be shown to be the result of fluctuations in Ca current.
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  • Masahide YOSHIDA, Takemi KOED
    1986 Volume 22 Issue 5 Pages 437-446
    Published: October 24, 1986
    Released on J-STAGE: July 21, 2010
    JOURNAL FREE ACCESS
    Yoshida, M. and Koeda, T. A note on responses of isolated guinea-pig tracheal strip preparation to electrical stimulation. Japanese Journal of Smooth Muscle Reserach, 1986, 22 (5), 437-446, Authors observed the mechanical response of the tracheal muscle to electrical stimulation usinonly one transverse strip preparation of isolated guinea-pig trachea, 4-5 mm in width, which included only one tracheal muscle strip.The effects of various pharmacological agents on these responses were also investigated. A biphasic response which is a contractile response followed by a relaxing response usually appeared when the preparation was stimulated with rectangular pulses (50 volt, 0.5 msec) at 40 Hz for a period of 5 sec. A monophasic contractile response also appeared, only rarely, but this response was shifted to the biphasic response as the resting tonus level of the preparation gradually increased in the course of the experiment. When the preparation was stimulated electrically at intervals of 15 min, the resting tonus level of the preparation gradually decreased and it subsequently reached a stable state. Then the amplitude of contractile response and depth of relaxing response in the biphasic response evoked by electrical stimulation of constant condition were, respectively, almost constant, whenever the preparation was stimulated at intervals of 15 min. The amplitude of monophasic contractile response which appeared only rarely was relatively constant to every trial of electrical stimulation throughout the experiment. The amplitude of contractile response and depth of relaxing response in the biphasic response were 283±65 mg (mean±SD, n=10) and 293±93 mg (mean±SD, n=10), respectively. The monophasic contractile response was abolished by atropine (5×10-2 g/ml) or tetrodotoxin (2×10-7 g/ml). The contractile response in the biphasic response was abolished by atropine (5×10-7 g/ml). In the presence of atropine (5×10-7 g/ml), therefore, only the relaxing response appeared. This relaxing response was respectively reduced by guanethidine (1×10-5 g/ml-1×10-6 g/ml) and propranolol (1×10-5 g/ml-1×10-6 g/ml), but complete inhibition was never seen. These findings suggest that the excitatory innervation is cholinergic and the inhibitory innervation is both adrenergic and non-adrenergic. In addition, from the results of this work it is clear that the preparation used by the authors are good enough to observe the electrical stimulation-induced response of the preparation.
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  • Shinzo KITAHARA
    1986 Volume 22 Issue 5 Pages 447-465
    Published: October 24, 1986
    Released on J-STAGE: July 21, 2010
    JOURNAL FREE ACCESS
    Canine intestine 80% was resected, and the post-operative residual intestine was observed on its motor-function in time course by the use of electro-myographic test. The results are as follows.
    1. Post-operative frequency of electric discharge was reduced, and it was reduced at the residual jejunum in time course, while it was nearly constant at the residual ileum.
    2. Residual jejunum showed no significant change in the continuous time and amplitude of spike burst after operation. While residual ileum showed the post-operative increasing tendency.
    3. When the ratio of active phase, average of spike burst occurrences in one minute was regarded as index of intestinal excitability, the excitability was increased in both jejunum and ileum at earlier stage after operation. However, the ileum showed earlier recovery tendency.
    4. Electric discharge interval after resection became irregular, and the occurrence rate of antiperistaltic propagation was elevated.
    5. Residual ileum showed a longer tendency of one series of MMC after operation. Residual jejunum showed numerous occurrences of MMC up to 3 months after operation, there after, occurring interval of MMC was extended, and MMC-series showed the shortened tendency.
    6. Conduction velocity was higher after operation at the residual ileum, and it was not recovered even after 2-3 years, while residual jejunum showed a recovery trend with the peak at the 6th week after operation.
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  • Shogo MURATA
    1986 Volume 22 Issue 5 Pages 467-482
    Published: October 24, 1986
    Released on J-STAGE: July 21, 2010
    JOURNAL FREE ACCESS
    To clarify the effect of synthetic motilin on gastric motility, the electromyograms after the bolus injection of synthetic motilin in dogs were investigated.
    The results were summarized as follows:
    1. After the bolus injection of synthetic motilin, the discharge interval was shortened and the propagation velosity was accelerated.
    Therefore, synthetic motilin stimulated gastric muscle in dogs.
    2. The dose-response effect of synthetic motilin on discharge interval was observed. On propagation velocity, the dose-response effect was observed, too.
    3. Between motilin and secretin, competitive antagonistic action was observed on electromyographic study.
    4. On the occasion of the combined use of motilin and tetragastrin, additive effect was observed.
    5. After atropine injection, synthetic motilin stimulated gastric muscle.
    6. After vagotomy, synthetic motilin also stimulated gastric muscle.
    7. After feeding, it was appeared that synthetic motilin did not stimulated gastric muscle.
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