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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1988-6-24
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pubmed:abstractText |
The age-related alterations in the number and size of alpha- and gamma-motoneurons were studied in the medial gastrocnemius (MG) motor nuclei in rats at four ages: young (5 months), middle aged (10-13 months), old (26 months), and very old (31 months). Small volumes (0.1-0.5 microliter) of 40% horseradish peroxidase (HRP) solution were injected into the cut MG nerve bilaterally by using glass micropipettes and a pressure injection system. The number, position, and soma size (average soma diameter) of MG motoneurons were determined by using photographic maps of each TMB-stained section. The total number of myelinated axons was counted in seven MG nerves from the same animals. The average soma diameters in each MG nucleus were distributed bimodally; cells with average diameter greater than 21.0-24.0 micron were presumed to be alpha-motoneurons and those with smaller diameters were presumed to be gamma. The mean number of presumed alpha-motoneurons was significantly less in the old and very old groups as compared with the young and middle-aged. In contrast, the number of presumed gamma-motoneurons was the same across age groups. The mean average soma diameter of both alpha- and gamma-motoneurons was smaller in the old animals. The apparent decrease in the total number of labeled motoneurons in old animals was also reflected in a decrease in myelinated axon counts. We conclude that there is a significant decrease in the absolute numbers of motoneurons in rats aged 26 months and older, with most of the decrease occurring among the larger alpha-motoneurons.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0021-9967
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
269
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
425-30
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:3372722-Aging,
pubmed-meshheading:3372722-Animals,
pubmed-meshheading:3372722-Cell Count,
pubmed-meshheading:3372722-Horseradish Peroxidase,
pubmed-meshheading:3372722-Male,
pubmed-meshheading:3372722-Motor Neurons,
pubmed-meshheading:3372722-Muscle Development,
pubmed-meshheading:3372722-Muscles,
pubmed-meshheading:3372722-Nerve Fibers, Myelinated,
pubmed-meshheading:3372722-Rats,
pubmed-meshheading:3372722-Rats, Inbred F344,
pubmed-meshheading:3372722-Spinal Cord
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pubmed:year |
1988
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pubmed:articleTitle |
Medial gastrocnemius motor nucleus in the rat: age-related changes in the number and size of motoneurons.
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pubmed:affiliation |
Department of Kinesiology, Tokyo Metropolitan Institute of Gerontology, Japan.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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