Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Axotomy”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1979

Initiation and time course of mitosis of non-neuronal cells after spinal motoneuron axotomy.

The mitotic response of non-neuronal cells following motor axon transection was measured after in vitro incorporation of [3H]thymidine in frog spinal cord. This predominantly ipsilateral response occurs more rapidly and is of greater magnitude when motor axons are unilaterally transected at the ventral root than after sciatic nerve transection. No increase in incorporation occurred when regenerating fibers were transected a second time before reinnervation, but an increase was observed when the second operation was performed after the formation of functional neuromuscular connections had taken place. Autoradiographic studies after dorsal or ventral root transection showed that the distribution of labeled cells approximated the anatomical extent of the injured cellular elements within the spinal cord. These data are discussed in relation to the characteristics of the dividing cells and the nature of the events eliciting mitosis.

Animals↗
PubMed1981

Retinal ganglion cell response to axotomy and nerve growth factor antiserum treatment in the regenerating visual system of the goldfish (Carassius auratus): an in vivo and in vitro analysis.

In vitro nerve growth factor (NGF) antiserum (anti-NGF) treatment was found to significantly depress retinal ganglion cell neurite outgrowth in goldfish explant culture. Goldfish retinas, conditioned by a 14-day prior optic nerve crush, demonstrated a significant dose response inhibition of neurite outgrowth if incubated with various concentrations of the antiserum (i.e. concentrations from full strength to 1:100) before explantation for tissue culture. NGF added to the incubation medium containing antiserum partially eliminated the inhibition of neurite outgrowth during the first 4 days of explant culture. Antiserum treatment at the higher concentrations (i.e. full strength and 1:1.5 dilution) caused a cessation of nerve growth from explants between culture days 3 and 4. However, controls at this time still exhibited vigorous neurite outgrowth. In vivo treatment with anti-NGF administered intraocularly at 7 days after optic nerve crush (i.e. 7 DPA) was found to significantly reduce the size and complexity of retinal ganglion cell nucleoli when analyzed morphometrically at 14 DPA. No other cell parameters measured (i.e. cell size, nuclear size, cell/nuclear ratios and mitochondrial, Golgi and RER densities) were found to be affected by the single antiserum treatment.

Animals↗
PubMed1981

Lingually induced inhibitory postsynaptic potentials in hypoglossal motoneurons after axotomy.

Inhibitory postsynaptic potentials (IPSPs) produced in axotomized hypoglossal motoneurons by stimulation of the lingual nerve were explored in cats. In the ipsilateral lingual afferent synapses, the effectiveness of inhibitory synapses for the long-lasting IPSP was diminished in axotomized hypoglossal motoneurons earlier after transection of the hypoglossal nerves, than the effectiveness of inhibitory synapses for the short-lasting IPSP.

Animals↗
PubMed1983

Reinnervation of the ventral root L7 from ventral horn neurons following intramedullary axotomy in adult cats.

Through small longitudinal incisions in the ventral funiculus of the adult cat spinal cord the intramedullary portions of motoraxons forming the L7 ventral root were divided. The animals were sacrificed by glutaraldehyde-perfusion 1-15 weeks postoperatively. In some cases this was preceded by HRP injection into large L7 ventral horn neurons. Sections from the lesioned ventral funiculus and the denervated ventral root L7 were examined by light and electron microscopy. During the first postoperative month increasing numbers of unmyelinated and thinly myelinated large-diameter axons coursed through the lesion and entered the denervated ventral root. Occasional neuroma-like formations were also found in the lesion area. After 5 weeks survival clusters of regenerating axons reached the distal end of the L7 ventral root. Light microscopic examination of Vibratome sections from HRP-injected animals showed that at least some regenerated axons come from large neurons, presumably alpha-motoneurons, in the ventral horn motor nuclei. Most of the examined labeled regenerated axons reached the CNS/PNS junction of the ventral root but a few followed a grossly aberrant course and/or terminated within the lesion. These observations show that regeneration of large-diameter axons through a CNS-lesion is possible. Both the intrinsic regenerative capacity of the axotomized neurons and the presence of a denervated ventral root in the immediate vicinity are likely to be contributing factors with respect to this example of successful CNS axon regeneration.

Animals↗
PubMed1985

'Dendraxons' in regenerating motoneurons in the cat: do dendrites generate new axons after central axotomy?

The intramedullary portions of motor axons in the spinal cord of adult cats were divided by longitudinal incisions in the ventral funiculus. After 7-11 weeks ventral horn neurons were injected intracellularly with horseradish peroxidase. Regenerating processes of the injected cells were studied with light- and electron-microscopical techniques. The results show that in some cases more than one axon-like myelinated regenerating process was found in a single neuron. Moreover, in such cases at least one of the processes seemed to be of dendritic origin.

Animals↗
PubMed1985

Removal of optic tectum prolongs the cell body reaction to axotomy in goldfish retinal ganglion cells.

Injury to the optic axons of goldfish elicits dramatic changes in the cell bodies of the neurons from which these axons arise, the retinal ganglion cells. The changes include a large increase in cell size and in synthesis and axonal transport of protein. The cells begin to return to normal about 3 weeks after the injury, when the axons invade the contralateral (homotopic) lobe of the optic tectum, and recovery is essentially complete by 8-10 weeks after the lesion. However, if the homotopic lobe of the tectum was removed at the time of nerve crush, we found that the cell body reaction was greatly prolonged. The cells remained enlarged, and [3H]proline incorporation and fast axonal transport of protein remained elevated, until at least 10-12 weeks after nerve crush, although by this time most of the regenerating axons had probably regained their normal length and many had entered the remaining ipsilateral (heterotopic) lobe of the tectum. The cells showed partial recovery by the latest time tested, 26 weeks after nerve crush, when the projections from the two eyes had segregated into separate bands in the heterotopic tectal lobe.

Animals↗
PubMed1986

The origins of the sciatic nerve and changes in neuropeptides after axotomy: a double labelling study using retrograde transport of true blue and vasoactive intestinal polypeptide immunohistochemistry.

One month after sciatic nerve section, only dorsal root ganglion cells which take up True blue applied to the cut end of the nerve show vasoactive intestinal polypeptide immunoreactivity. This indicates that VIP expression is only in cells with damaged axons. Motor axons with True blue-positive perikarya in the ventral horn originate from the fourth to sixth lumbar segments whereas unmyelinated and small myelinated sensory nerves terminate in the third to fifth lumbar segments of the spinal cord.

Animals↗
PubMed1987

Peripheral nerve implant effects on survival of retinal ganglion layer cells after axotomy initiated by a penetrating lesion.

A lesion paradigm involving a small penetrating incision made through the sclera, choroid and retina of the adult rat eye creates a unique environment for the study of the damaged retina. More specifically, the dependable formation of a small focal retinal lesion makes this an ideal model for the determination of conditions that may stimulate retinal regeneration, wound repair and/or cell survival. Our previous studies have indicated that the placement of a desheathed peripheral nerve implant (PNI) into the lesioned adult rat eye: (1) initiated the rescue of retinal tissue that would normally die due to trauma; and (2) maintained the thickness and organization of most retinal layers adjacent to the lesion site, particularly the retinal ganglion cell layer (RGL). We report in the present work that a more detailed analysis of the RGL revealed a significant increase in the survival of axotomized neurons within this layer in the presence of a PNI over an 8-week post-implantation period. More specifically, there was a 60% loss of control RGL cells axotomized by the lesion 3 weeks previously in contrast to only a 30% loss in those tissues exposed to a PNI. Additional RGL cell size distribution studies point to the fact that the PNI appeared to affect the increased survival of cells greater than or equal to 70 micron2. Also the PNI effect demonstrated a specificity of response when tested against the influence of a tendon or suture implant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Piezoelectric guidance channels enhance regeneration in the mouse sciatic nerve after axotomy.

Piezoelectric nerve guidance channels made of polyvinylidene fluoride (PVDF) were evaluated in a transected mouse sciatic nerve model. Poled PVDF channels were compared to unpoled PVDF channels after 4 and 12 weeks of implantation. In all animals, the proximal and distal nerve stumps were bridged by a continuous nerve cable. Nerves regenerated in poled channels contained a higher number of myelinated axons than those regenerated in unpoled channels at both time periods. We conclude that piezoelectric nerve guidance channels enhance peripheral nerve regeneration and provide a tool to investigate the influence of electrical activity on nerve regeneration.

Animals↗
PubMed1991

Selective expression of Jun proteins following axotomy and axonal transport block in peripheral nerves in the rat: evidence for a role in the regeneration process.

Expression of the protein products of the immediate-early genes (IEGs), members of the fos, jun and krox families (Jun, Fos, and Krox, resp.) was investigated in the spinal cord and sensory ganglia (DRG) of normal rats; and following transection of, block of axonal transport in, or electrical stimulation of their peripheral axons. The nuclei of many moto- and DRG neurons showed a faint basal immunoreactivity (IR) for Jun proteins, but not for Fos or Krox proteins. There was a strong and selective induction of Jun-IR in moto- and DRG neurons after peripheral nerve transection or crush, or colchicine- or vinblastine-induced block of axonal transport. The Jun-IR induced by nerve transection disappeared after nerve regeneration. In contrast, Jun, Fos and Krox proteins were all induced transynaptically in spinal dorsal horn neurons following electrical stimulation of the C-fibers in the afferent nerves. Thus in differentiated neurons in vivo these IEG proteins can be expressed either independently or concomitantly depending on the type of stimulus.

Animals↗