2007 Fiscal Year Final Research Report Summary
Mechanisms of Retarded Recovery of Muscular Fatigue After Vigorous Contraction
| Project/Area Number |
17300209
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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 |
Sports science
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| Research Institution | Hiroshima University |
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Principal Investigator |
WADA Masanobu Hiroshima University, Graduate School of Integrated Arts and Sciences, Professor (80220961)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUNAGA Satoshi Osaka City University, Research Center for Urban Health and Sports, Lecturer (70221588)
MISHIMA Takaaki Hachinohe Junior College, Department of Pre-School Education, Lecturer (00461707)
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| Project Period (FY) |
2005 – 2007
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| Keywords | degrees of protease activation and / or of oligomeri / sarcoplasmic reticulum / muscular fatigue / calcium ion / muscle contraction / skeletal muscle |
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| Research Abstract |
The sarcoplasmic reticulum (SR), a membrane structure in all mu grip evils that closely surrounds each myofibril, plays a critical role in the regulation of intracellular free Ca^<2+> concentration. The present study was undertaken to address the mechanisms underlying retarded recovery of muscular fatigue after vigorous contraction, with focus on changes in the Ca^<2+>-handling ability of the SR Experiments conducted with rat skeletal muscles provided the findings described below.
1. Repetitive muscle contractions hind limb skeletal muscles induced by electric nerve stimulation caused //depressions in SR Ca^<2+>-ATPase activity in the superficial (GS) and deep regions of the gastrocnemius at 1 and 5 min of stimulation, respectively and 2/no changes in the activity in the soleus.
2. Thirty-min recovery after 5-min stimulation resulted in restorations of contraction-induced decreases in SR Ca^<2+>-ATPase activity in GS. However, at this time point, a carbonyl content comprised in the enzym
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e and a fluorescein isothiocyanate (FITC) binding to the enzyme remained increased and decreased, respectively
3. Extraction of glycogen from the SR membrane by treatment with glucoamylase evoked decreases in glycogen phosphorylase on the SR and elevations of FITC binding. However, these alterations were not accompanied by changes in the catalytic activity of SR Ca^<2+>-ATPase.
These findings do not implicate oxidative modifications of protein, structural alterations to the nucleotide-binding domain or depletion of glycogen as a contributor to contraction-induced depressions in the Ca^<2+>-handling ability of the SR It has previously been shown that the rate of restoration of the impaired SR Ca-uptake capacity induced by vigorous muscle contraction varies among different contraction modes, even when immediately after the cessation of contraction, the extent of the depression in SR Ca^<2+>-uptake capacity is similar The distinct restoration rate of SR Ca^<2+>-handling capacity could be explained by the varied degrees of protease activation and/or of oligomerization of SR Ca^<2+-> ATPase. Less
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