ON THE COUPLING RELATION BETWEEN ACTION POTENTIAL AND MECHANICAL RESPONSE DURING REPETITIVE STIMULATION IN FROG SARTORIUS MUSCLE
1962 Volume 12 Issue 3 Pages 324-336
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1962 Volume 12 Issue 3 Pages 324-336
1. The coupling relation between action potential and mechanical response during repetitive stimulation was investigated using the sartorius muscle of the frog.
2. The course of decrease in spike height obtained by partition method coincided with that by intracellular recording.
3. The coupling efficiency between spike height and peak tension during repetitive stimulation was improved at first during staircase phenomenon and then it decreased progressively.
4. Fatigue, higher stimulating frequency, and heavy load resulted in a deficiency of coupling process, especially the mechano-chemical process.
5. At higher temperature, the coupling efficiency for single stimulus was decreased, but for repetitive stimulation the period of staircase phenomenon was greatly prolonged and the rate. of decrease in spike height became much slower.
6. The height of negative after-potential or the spike duration showed a poor correlation with peak tension during repetitive stimulation.
7. When the muscle was stimulated at 2c/sec through nerve, transmission fatigue was observed in the range beyond 300 stimuli.
8. The electro-mechanical coupling, as the complex of the activation process for contraction and the energy mobilizing process in contraction, was discussed.
