| Project/Area Number |
07458222
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
神経・脳内生理学
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| Research Institution | Kyushu University |
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Principal Investigator |
OHTSUKI Iwao Kyushu University, Faculty of Medicine, Department of Clinical Pharmacology : Professor, 医学部, 教授 (70009992)
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| Co-Investigator(Kenkyū-buntansha) |
YANAGA Fumi Kyushu University, Faculty of Medicine, Department of Clinical Pharmacology : Re, 医学部, 助手 (50274436)
MORIMOTO Sachio Kyushu University, Faculty of medicine, Department of Clinical Pharmacology : As, 医学部, 助教授 (50202362)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1995: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | muscle contraction / Ca-sensitivity / acidosis / troponin / pH-sensitivity |
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| Research Abstract |
The Ca^<2+>-sensitivity of contraction of striated muscles is lowered by reducing pH.The extent of this Ca^<2+>-sensitivity decrease is in the order of cardiac, fast skeletal and slow skeletal muscles. In order to examine the role of troponin C and I in this pH-dependent change in the Ca^<2+>-sensitivity, the effect of various hybrid combinations of troponin C and I from three kinds of striated muscles was studied on the Ca^<2+>-sensitive contraction of rabbit cardiac skinned fibers, using the troponin-exchange technique. As a result, the extent of the decrease in the Ca^<2+>-sensitivity on reducing pH was found to be in the following order :
CC = FC > CF = FF > SC = SF (TnI・TnC)
C,cardiac ; F,fast ; S,slow
These results clearly indicate that the change in the Ca^<2+>-sensitivity by pH-reduction is determined not only by the species of Ca^<2+>-receptive subunit (troponin C) but also by the interaction of troponin C with troponin I.
Human cardiac troponin subunits were cloned, expressed in E.Coli and purified, and their action was investigated in skinned fibers. Involvement of troponin in the pH-sensitivity of Ca^<2+>-activated contraction of scallpo striated muscles was also demonstrated.
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