Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy
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Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy. / Fenrich, Keith K; Skelton, Nicole; MacDermid, Victoria E; Meehan, Claire Francesca; Armstrong, Stacey; Neuber-Hess, Monica S; Rose, P Ken.
In: Journal of Comparative Neurology, Vol. 502, No. 6, 2007, p. 1079-97.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy
AU - Fenrich, Keith K
AU - Skelton, Nicole
AU - MacDermid, Victoria E
AU - Meehan, Claire Francesca
AU - Armstrong, Stacey
AU - Neuber-Hess, Monica S
AU - Rose, P Ken
N1 - (c) 2007 Wiley-Liss, Inc.
PY - 2007
Y1 - 2007
N2 - Following proximal axotomy, several types of neurons sprout de novo axons from distal dendrites. These processes may represent a means of forming new circuits following spinal cord injury. However, it is not know whether mammalian spinal interneurons, axotomized as a result of a spinal cord injury, develop de novo axons. Our goal was to determine whether spinal commissural interneurons (CINs), axotomized by 3-4-mm midsagittal transection at C3, form de novo axons from distal dendrites. All experiments were performed on adult cats. CINs in C3 were stained with extracellular injections of Neurobiotin at 4-5 weeks post injury. The somata of axotomized CINs were identified by the presence of immunoreactivity for the axonal growth-associated protein-43 (GAP-43). Nearly half of the CINs had de novo axons that emerged from distal dendrites. These axons lacked immunoreactivity for the dendritic protein, microtubule-associated protein2a/b (MAP2a/b); some had GAP-43-immunoreactive terminals; and nearly all had morphological features typical of axons. Dendrites of other CINs did not give rise to de novo axons. These CINs did, however, each have a long axon-like process (L-ALP) that projected directly from the soma or a very proximal dendrite. L-ALPs were devoid of MAP2a/b immunoreactivity. Some of these L-ALPs projected through the lesion and formed bouton-like swellings. These results suggest that proximally axotomized spinal interneurons have the potential to form new connections via de novo axons that emerge from distal dendrites. Others may be capable of regeneration of their original axon.
AB - Following proximal axotomy, several types of neurons sprout de novo axons from distal dendrites. These processes may represent a means of forming new circuits following spinal cord injury. However, it is not know whether mammalian spinal interneurons, axotomized as a result of a spinal cord injury, develop de novo axons. Our goal was to determine whether spinal commissural interneurons (CINs), axotomized by 3-4-mm midsagittal transection at C3, form de novo axons from distal dendrites. All experiments were performed on adult cats. CINs in C3 were stained with extracellular injections of Neurobiotin at 4-5 weeks post injury. The somata of axotomized CINs were identified by the presence of immunoreactivity for the axonal growth-associated protein-43 (GAP-43). Nearly half of the CINs had de novo axons that emerged from distal dendrites. These axons lacked immunoreactivity for the dendritic protein, microtubule-associated protein2a/b (MAP2a/b); some had GAP-43-immunoreactive terminals; and nearly all had morphological features typical of axons. Dendrites of other CINs did not give rise to de novo axons. These CINs did, however, each have a long axon-like process (L-ALP) that projected directly from the soma or a very proximal dendrite. L-ALPs were devoid of MAP2a/b immunoreactivity. Some of these L-ALPs projected through the lesion and formed bouton-like swellings. These results suggest that proximally axotomized spinal interneurons have the potential to form new connections via de novo axons that emerge from distal dendrites. Others may be capable of regeneration of their original axon.
KW - Age Factors
KW - Animals
KW - Axotomy
KW - Biological Markers
KW - Biotin
KW - Cats
KW - Dendrites
KW - Disease Models, Animal
KW - Functional Laterality
KW - GAP-43 Protein
KW - Growth Cones
KW - Immunohistochemistry
KW - Interneurons
KW - Microtubule-Associated Proteins
KW - Nerve Regeneration
KW - Neuronal Plasticity
KW - Presynaptic Terminals
KW - Recovery of Function
KW - Reproducibility of Results
KW - Spinal Cord Injuries
U2 - 10.1002/cne.21362
DO - 10.1002/cne.21362
M3 - Journal article
C2 - 17447249
VL - 502
SP - 1079
EP - 1097
JO - The Journal of Comparative Neurology
JF - The Journal of Comparative Neurology
SN - 0021-9967
IS - 6
ER -
ID: 40314841