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>Mode of stimulation by aldosterone of the sodium efflux in barnacle muscle fibres: effects of ouabain, ethacrynic acid, diphenylhydantoin, (ATPMg)(2-), adenine translocase inhibitors, pyruvate and oxythiamine.
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Mode of stimulation by aldosterone of the sodium efflux in barnacle muscle fibres: effects of ouabain, ethacrynic acid, diphenylhydantoin, (ATPMg)(2-), adenine translocase inhibitors, pyruvate and oxythiamine.
1. A study has been made of the nature of the delayed stimulation caused by external aldosterone in barnacle fibres pre-exposed to aldosterone. 2. (i) Microinjection of 0-5 M-ATPMg2- caused only a small but prompt rise in the Na efflux. (ii) Microinjection of 0-5 M-ATPMg2- followed by external application of 10(-5)M aldosterone greatly augmented the magnitude of the delayed stimulation. The response was dose-dependent, as well as dependent on the concentration of external K+ and H+, but not Na+, Ca2+ or Mg2+. (iii) External application of 10(-5) M aldosterone for 30 min followed by its withdrawal from the bathing medium failed to bring about delayed stimulation. By contrast, fibres into which ATP had been injected showed delayed stimulation under these conditions. 3. Microinjection of actinomycin-D or spironolactone SC-14266 into fibres into which ATP had been injected followed by external application of aldosterone resulted in complete abolition of the delayed stimulation. 4. Delayed stimulation was reduced whether ATP had been injected or not by prior external application of 10(-4)M ouabain or internal application of 8 x 10(-2)M ethacrynic acid. It was completely abolished by prior application of ouabain externally and ethacrynic acid internally, or only 10(-4)M diphenylhydantoin externally. 5. (i) Microinjection of atractyloside or bongkrekic acid caused a substantial fall in the resting Na efflux. Bonkrekic acid proved more powerful than atractyloside. Microinjection of 0-05 M-ATPMg2- into fibres poisoned with 2-0 x 10(-2)M bongkrekic acid completely restored the Na efflux.
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机译:1.已经对预先暴露于醛固酮的藤壶纤维中外部醛固酮引起的延迟刺激的性质进行了研究。 2.(i)微量注射0-5 M-ATPMg2-仅引起少量但迅速的Na流出增加。 (ii)显微注射0-5 M-ATPMg2-,然后外用10(-5)M醛固酮大大增加了延迟刺激的幅度。反应是剂量依赖性的,也取决于外部K +和H +的浓度,而不取决于Na +,Ca2 +或Mg2 +。 (iii)外部应用10(-5)醛固酮30分钟,然后将其从沐浴介质中撤出未能引起延迟刺激。相反,在这些条件下,向其中注入ATP的纤维显示出延迟的刺激。 3.将放线菌素-D或螺内酯SC-14266微注射入已注射ATP的纤维中,然后外用醛固酮可完全消除延迟刺激。 4.不论事先注射10(-4)M哇巴因还是内部使用8 x 10(-2)M乙炔酸,无论是否注射ATP,都能减少延迟刺激。事先在外部使用哇巴因和内部在使用乙炔酸,或在外部仅使用10(-4)M二苯乙内酰脲彻底清除了它。 5.(i)微量注射白术甙或邦克里奇酸引起静息钠流出明显下降。事实证明,Bonkrekic酸比白术甙更有效。将0-05 M-ATPMg2-微量注射到2-0 x 10(-2)M邦克里奇酸中毒的纤维中可完全恢复Na流出。
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