Abstract
Severe muscle atrophy occurs after complete denervation. Here, Embryonic Day 14-15 ventral spinal cord cells were transplanted into the distal tibial nerve stump of adult female Fischer rats to provide a source of neurons for muscle reinnervation. Our aim was to characterize the properties of the reinnervated motor units and muscle fibers. Some reinnervated motor units contracted spontaneously. Electrical stimulation of the transplants at increasing intensity produced an average (± SE) of 7 ± 1 electromyographic and force steps. Each signal increment represented the excitation of another motor unit. These reinnervated units exerted an average force of 12.0 ± 1.5 mN, strength similar to that of control fatigue-resistant units. Repeated transplant stimulation depleted 17% of the muscle fibers of glycogen, an indication of some functional reinnervation. Reinnervated (glycogen-depleted), denervated (no cells transplanted), and control fibers were of histochemical type I, IIA, or IIB. Fibers of the same type were grouped after reinnervation. The proportion of fiber types also changed. Reinnervated fibers were primarily type IIA, whereas most fibers in denervated and control muscles were type IIB. Reinnervated fibers of each type had significantly larger cross-sectional areas than the corresponding fiber types in denervated muscles. These data suggest that neurons with different properties can reside in the unusual environment of the adult rat peripheral nerve, make functional connections with muscle, specify muscle fiber type, and reduce the amount that each type atrophies.
| Original language | English |
|---|---|
| Pages (from-to) | 25-31 |
| Number of pages | 7 |
| Journal | Experimental Neurology |
| Volume | 180 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 1 2003 |
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Keywords
- Axon regeneration
- Embryonic ventral spinal cord
- Glycogen depletion
- Muscle denervation
- Muscle fiber types
- Muscle reinnervation
- Transplantation
ASJC Scopus subject areas
- Neurology
- Neuroscience(all)
Cite this
Properties of medial gastrocnemius motor units and muscle fibers reinnervated by embryonic ventral spinal cord cells. / Thomas, Christine K; Sesodia, Sanjay; Erb, Daniel E.; Grumbles, Robert M.
In: Experimental Neurology, Vol. 180, No. 1, 01.03.2003, p. 25-31.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Properties of medial gastrocnemius motor units and muscle fibers reinnervated by embryonic ventral spinal cord cells
AU - Thomas, Christine K
AU - Sesodia, Sanjay
AU - Erb, Daniel E.
AU - Grumbles, Robert M.
PY - 2003/3/1
Y1 - 2003/3/1
N2 - Severe muscle atrophy occurs after complete denervation. Here, Embryonic Day 14-15 ventral spinal cord cells were transplanted into the distal tibial nerve stump of adult female Fischer rats to provide a source of neurons for muscle reinnervation. Our aim was to characterize the properties of the reinnervated motor units and muscle fibers. Some reinnervated motor units contracted spontaneously. Electrical stimulation of the transplants at increasing intensity produced an average (± SE) of 7 ± 1 electromyographic and force steps. Each signal increment represented the excitation of another motor unit. These reinnervated units exerted an average force of 12.0 ± 1.5 mN, strength similar to that of control fatigue-resistant units. Repeated transplant stimulation depleted 17% of the muscle fibers of glycogen, an indication of some functional reinnervation. Reinnervated (glycogen-depleted), denervated (no cells transplanted), and control fibers were of histochemical type I, IIA, or IIB. Fibers of the same type were grouped after reinnervation. The proportion of fiber types also changed. Reinnervated fibers were primarily type IIA, whereas most fibers in denervated and control muscles were type IIB. Reinnervated fibers of each type had significantly larger cross-sectional areas than the corresponding fiber types in denervated muscles. These data suggest that neurons with different properties can reside in the unusual environment of the adult rat peripheral nerve, make functional connections with muscle, specify muscle fiber type, and reduce the amount that each type atrophies.
AB - Severe muscle atrophy occurs after complete denervation. Here, Embryonic Day 14-15 ventral spinal cord cells were transplanted into the distal tibial nerve stump of adult female Fischer rats to provide a source of neurons for muscle reinnervation. Our aim was to characterize the properties of the reinnervated motor units and muscle fibers. Some reinnervated motor units contracted spontaneously. Electrical stimulation of the transplants at increasing intensity produced an average (± SE) of 7 ± 1 electromyographic and force steps. Each signal increment represented the excitation of another motor unit. These reinnervated units exerted an average force of 12.0 ± 1.5 mN, strength similar to that of control fatigue-resistant units. Repeated transplant stimulation depleted 17% of the muscle fibers of glycogen, an indication of some functional reinnervation. Reinnervated (glycogen-depleted), denervated (no cells transplanted), and control fibers were of histochemical type I, IIA, or IIB. Fibers of the same type were grouped after reinnervation. The proportion of fiber types also changed. Reinnervated fibers were primarily type IIA, whereas most fibers in denervated and control muscles were type IIB. Reinnervated fibers of each type had significantly larger cross-sectional areas than the corresponding fiber types in denervated muscles. These data suggest that neurons with different properties can reside in the unusual environment of the adult rat peripheral nerve, make functional connections with muscle, specify muscle fiber type, and reduce the amount that each type atrophies.
KW - Axon regeneration
KW - Embryonic ventral spinal cord
KW - Glycogen depletion
KW - Muscle denervation
KW - Muscle fiber types
KW - Muscle reinnervation
KW - Transplantation
UR - http://www.scopus.com/inward/record.url?scp=0037349834&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037349834&partnerID=8YFLogxK
U2 - 10.1016/S0014-4886(02)00024-9
DO - 10.1016/S0014-4886(02)00024-9
M3 - Article
C2 - 12668146
AN - SCOPUS:0037349834
VL - 180
SP - 25
EP - 31
JO - Experimental Neurology
JF - Experimental Neurology
SN - 0014-4886
IS - 1
ER -