著者

山内 一功 太田 勲

出版者

札幌医科大学医学部

雑誌

札幌医学雑誌 = The Sapporo medical journal = The Sapporo medical journal (ISSN:0036472X)

巻号頁・発行日

vol.47, no.6, pp.582-591, 1978-12-01

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Changes of mechanical and electrical responses in frog whole sartorius muscle surviving at a constant temperature (20±1℃) in normal Ringer solution, Ringer solution which was supplemented with antibiotics or modified Medium 199 were examined and the following results were obtained. 1. The peak tensions of both twitch and potassium contracture (K-contracture) decreased gradually with the lapse of time after immersion of whole sartorius muscles in normal Ringer solution. Twelve hours after the immersion, the peak tensions of twitch and K-contracture decreased to about 55% and 67% of the control, respectively. Sixteen hours after the immersion, the respective peak tensions decreased to about 10% of the control. However, the peak tension of caffeine contracture did not change up to 12 hours after immersion, whereas it decreased to about 20% of the control 16 hours after immersion. Whole sartorius muscles surviving more than 12 hours in normal Ringer solution assumed a milky color and contained fibers which had a granular appearence. Proliferation of bacteria was observed in normal Ringer solution in which muscle preparations survived more than 12 hours. 2. In whole muscle surviving in Ringer solution with antibiotics (penicillin 50U/ml plus streptomycin 10 μg/ml), the twitch tension decreased gradually with the lapse of time after the immersion and it decreased to about 10% at 24 hours after immersion. On the other hand, the time course of the inhibition of the magnitude of K-contracture tension showed two distinct phases ; the first phase in which the tension was inhibited very slowly and slightly (up to 36 hours after immersion), and the second phase in which tension was inhibited rapidly and completely. In addition, peak tension of caffeine contracture showed no changes up to 24 hours after the immersion whereas it decreased to about 23% of the control 48 hours after the immersion. 3. The magnitude of resting potential and the amplitude of action potential of fibers immersed in Ringer solution with antibiotics for 24 hours were quite similar to those of the control. Fourty-eight hours after the immersion, overshoot of action potential was not observed, although the magnitude of resting potential showed no changes. 4. Twitch was abolished 6 days after immersion of whole muscle in modified Medium 199, whereas K-contracture and caffeine contracture were observed even after 18 days of the immersion. On the basis of these results, the mechanism of inhibition of mechanical responses in surviving whole muscle was discussed.