1998 Fiscal Year Final Research Report Summary
Influence of running exercise on γmotoneuron activity
| Project/Area Number |
09670079
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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 |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Chukyo Women's University |
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Principal Investigator |
SATO Haruhiko Chukyo Women's University, Faculty of Wellness, Department of Sports and Fitness, Professor, 健康科学部・健康スポーツ科学科, 教授 (20080004)
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| Project Period (FY) |
1997 – 1998
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| Keywords | γmotoneuron / training / primary ending / adaptation / soleus / secondary ending / treadmill / rat |
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| Research Abstract |
It has been experietially well known for a long time that a physical performance can be accomplished by so-called 'training', repeating of the movement concerned. Recently, many studies have been reported on the scientific analysis of the training-induced adaptive changes in skeletal muscles and nueuromuscular junctions. However, there are a few reports on the neural mechanism for the adaptive changes induced in the central nervous system. γ motoneuron-muscle spindle system to modulate via its feed back circuit the contraction of the muscle could be essential for the establishment of the physical performance particularly required for an accurate special- and temporal-control of muscle contraction. In the present study, to examine whether or not γ motoneuron-muscle spindle system is influenced by physical training, the afferent responses of the muscle spindle endings to stretch of the muscle were analysed by recording the discharge activities of the Gia fibers from the primary endings as well as the GII fibers from the secondary endings in the soleus muscles of the rats (TR) which were loaded by the interval running on a treadmill at the speed of 40 m/min, and a comparison was made between trained rats and untrained rats (CR). In each afferent response of the spindle ending, peak frequency (P) at the end of stretch, static frequency 0.5 sec later and the dynamic index (DI), the difference between P and S were measured by detecting the respective instantaneous frequency. It was found that on the GIa fibers P and DI in TR were significantly greater than those in CR while on the GII fibers P, S and DI in TR than those in CR. No response pattern such a decreased P accompanied by an increased S in the GIa fiber was encountered. The results suggest that the adaptive changes such as the activated dynamic γ motoneuron are induced by running exercise.
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