| Project/Area Number |
08670063
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General physiology
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| Research Institution | Jikei University School of Medicine |
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Principal Investigator |
KURIHARA Satoshi Jikei University School of Medicine Department of Physiology (II) Professor, 医学部, 教授 (90057026)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1997: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1996: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | cardiac muscle / muscle length / troponin-C, / Ca sensitivity / Ca ion, / troponin-I, / acidosis, / isoproterenol / Ca感受性 / Caイオン |
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| Research Abstract |
Cardiac muscle contraction is significantly altered by a change in initial muscle length before contraction. This is considered to be due to the crossbridge-dependent change in the affinity of troponin-C (Tn-C) for Ca ion. The hypothesis was examined to measure the relation between Ca ion concentration and tension (pCa-tension relation) at different muscle lengths in intact and skinned preparations of mammalian cardiac muscles. In intact preparations, the papillary muscles treated with ryanodine were repetitively stimulated and tetanus was induced for measuring pCa-tension relation at different muscle lengths in the presence or absence of isoproterenol (ISO). ISO increased the length-dependent shift of pCa-tension relation. Thin trabeculae were treated with Triton X and stored in 50% glycerol containing relaxing solution. pCa-tension relations at different muscle lengths were measured before and after phosphorylation by A-kinase. After phosphorylation, length-dependent shift of pCa-tension relation was lessened. These results suggest that Tn-I and/or C-protein which can be phosphorylated by A-kinase might be involved in the signal transduction from crossbridges to Tn-C.The different effects of A-kinase dependent phosphorylation in intact and skinned preparation should be further investigated.
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