1991 Fiscal Year Final Research Report Summary
Analysis of mechanical hysteresis phenomena in muscular contraction.
| Project/Area Number |
02640565
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Teikyo University of Technology |
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Principal Investigator |
TSUCHIYA Teizo Faculty of Informatics, Liberal Arts and Sciences Professor, 教授 (30091036)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Skeletal muscle / Cross-bridge / stiffness / force |
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| Research Abstract |
1. Single fibres from the anterior tibialis muscle of Rana temporaria were stretched during fused tetanic contractions and released to shorten under very low load during force enhancement at various times after stretch.
2. The shortening records derived after force enhancement exhibited a larger and steeper initial transient than did those obtained in the control of isometric contraction, while the speed of shortening following the transient phase was the same in the both cases. This difference in the time course of shortening between during force enhancement and during control leads to a vertical shift of the shortening traces on the superimposed records. The shift was linearly related to force enhancement and the maximal one observed was more than 30 nm/half sarcomere.
3. A similar comparison was made between two cases on the records of the segment length which were defined by opaque markers on the fiber and the equivalent vertical shift to the above amount was observed.
4. So called "slack tests" were performed during force enhancement and during control isometric contraction and the shift of two lines was measured. The results thus obtained agreed well with those derived by load-clamp experiment.
5. The T2 analysis, the approach described by Huxley and Simmons ( ), was carried out during force enhancement after stretch and during control isometric contraction. T2 curve during force enhancement was observed to be shifted towards larger release amplitude by 10-15nm/h.s., which is considerably lower than the shift of amount referred in load-clamp experiment.
6. The results is interpreted to show that stretching a muscle fiber during activity leads to recruitment of parallel elasticity in the contractile system and to induce enhanced force after a preceding stretch. Recoil of this component may account for the greater amplitude of the initial shortening phase observed when the fiber is released to shorten after stretch.
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