Sensory neuron addition in juvenile rat: Time course and specificity

Farel, Paul B.

doi:10.1002/cne.10274

Cited by 28 publications

(26 citation statements)

References 48 publications

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“…This finding supports and extends previous studies in frog and rat DRGs (St Wecker and Farel, 1994;Meeker and Farel, 1997;Popken and Farel, 1997;Farel, 2002Farel, , 2003, which signaled differences between sensory ganglia and well defined neurogenic regions in CNS in which the birth of new neurons is the main strategy for the increase, or maintenance, of neuron numbers. Protracted differentiation could thus be a developmental strategy that confers an adaptive advantage to neural populations that need to respond to changes in their environment by adding or renewing neurons without the prerequisite of DNA synthesis or cell-cycle reentry.…”

Section: Overview and Future Directionssupporting

confidence: 91%

“…Recent stereological studies have confirmed the fact of neuron addition in adult rat DRG (Cecchini et al, 1993(Cecchini et al, , 1994(Cecchini et al, , 1995Popken and Farel, 1997;Ciaroni et al, 2000;Farel, 2002).…”

Section: Discussionmentioning

confidence: 80%

“…It was proposed that the new neurons in adult DRG could derive from differentiation of cells that at younger ages could not be recognized as neurons, and for that reason not be counted (St Wecker and Farel, 1994;Meeker and Farel, 1997;Popken and Farel, 1997;Farel, 2002). These cells are characterized by being positive to neuronal markers, such as neurofilament, but are not traceable when HRP is applied to the periphery (Farel, 2003), suggesting that they had not yet extended their peripheral axons.…”

Section: Discussionmentioning

confidence: 99%

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Primary Sensory Neuron Addition in the Adult Rat Trigeminal Ganglion: Evidence for Neural Crest Glio-Neuronal Precursor Maturation

Lagares¹,

Li²,

Zhou³

et al. 2007

J. Neurosci.

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It is debated whether primary sensory neurons of the dorsal root ganglia increase the number in adult animals and, if so, whether the increase is attributable to postnatal neurogenesis or maturation of dormant, postmitotic precursors. Similar studies are lacking in the trigeminal ganglion (TG). Here we demonstrate by stereological methods that the number of neurons in the TG of adult male rats nearly doubles between the third and eighth months of age. The increase is mainly attributable to the addition of small, B-type neurons, with a smaller contribution of large, A-neurons. We looked for possible proliferative or maturation mechanisms that could explain this dramatic postnatal expansion in neuron number, using bromodeoxyuridine (BrdU) labeling, immunocytochemistry for neural precursor cell antigens, retrograde tracing identification of peripherally projecting neurons, and in vitro isolation of precursor cells from adult TG explant cultures. Cell proliferation identified months after an extended BrdU administration was sparse and essentially corresponded to glial cells. No BrdU-labeled cell took up the peripherally injected tracer, and only a negligible number coexpressed BrdU and the pan-neuronal tracer neuron-specific enolase. In contrast, a population of cells not recognizable as mature neurons in the TG and neighboring nerve expressed neuronal precursor antigens, and neural crest glioneuronal precursor cells were successfully isolated from adult TG explants. Our data suggest that a protracted maturation process persists in the TG that can be responsible for the neuronal addition found in the adult rat.

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Section: Overview and Future Directionssupporting

confidence: 91%

Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Primary Sensory Neuron Addition in the Adult Rat Trigeminal Ganglion: Evidence for Neural Crest Glio-Neuronal Precursor Maturation

Lagares¹,

Li²,

Zhou³

et al. 2007

J. Neurosci.

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“…Others have reported morphometric evidence for the formation of new neurons in postnatal or adult rat DRG as a normal process of development Popken and Farel, 1997;Farel, 2002;Guena et al, 2002). In a previous study using oral BrdU administration via drinking water for 1 month after sciatic transection, we found only a handful of BrdUlabeled ipsilateral DRG neurons after 2 months (Groves et al, 2003).…”

Section: Neurogenesis In Adult or Postnatal Dorsal Root Gangliamentioning

confidence: 86%

Effects of systemically administered NT‐3 on sensory neuron loss and nestin expression following axotomy

Kuo¹,

Simpson²,

Schänzer³

et al. 2005

J of Comparative Neurology

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Previous work has shown that administration of the neurotrophin NT-3 intrathecally or to the proximal stump can prevent axotomy-induced sensory neuron loss and that NT-3 can stimulate sensory neuron differentiation in vitro. We have examined the effect of axotomy and systemic NT-3 administration on neuronal loss, apoptosis (defined by morphology and activated caspase-3 immunoreactivity), and nestin expression (a protein expressed by neuronal precursor cells) in dorsal root ganglia (DRG) following axotomy of the adult rat sciatic nerve. Systemic administration of 1.25 or 5 mg of NT-3 over 1 month had no effect on the incidence of apoptotic neurons but prevented the overall loss of neurons seen at 4 weeks in vehicle-treated animals. Nestin-immunoreactive neurons began to appear 2 weeks after sciatic transection in untreated animals and steadily increased in incidence over the next 6 weeks. NT-3 administration increased the number of nestin-immunoreactive neurons at 1 month by two- to threefold. Nestin-IR neurons had a mean diameter of 20.78 +/- 2.5 microm and expressed the neuronal markers neurofilament 200, betaIII-tubulin, protein gene product 9.5, growth associated protein 43, trkA, and calcitonin gene-related peptide. Our results suggest that the presence of nestin in DRG neurons after nerve injury is due to recent differentiation and that exogenous NT-3 may prevent neuron loss by stimulating this process, rather than preventing neuron death.

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“…To determine the accuracy of profile counts in frozen material, sets of three consecutive 8-m sections that had been immunoreacted for Substance P (SP) were selected from the middle third of DRG L 4 of each of four P5 and four P100 rats (Farel, 2002). Digital images were captured, printed, and assembled into collages at a final magnification of 400ϫ.…”

Section: Studies In the Ratmentioning

confidence: 99%

Trust, but verify: The necessity of empirical verification in quantitative neurobiology

Farel

2002

Anat. Rec.

Self Cite

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The preferred procedure for estimating neuron number has been the subject of intense discussion. Sampling error, systematic bias, and the physical properties of the tissue examined all contribute to the possibility that estimates may not reflect actual neuron number. Even when restricting analysis to a particular, well-defined structure such as dorsal root ganglia, these factors act in a manner that varies with maturity of the animal, species, fixation, processing, and neuron size. These considerations reinforce the necessity of comparing estimates with the actual number of neurons as determined by three-dimensional reconstructions. Anat Rec (New Anat) 269:157-161, 2002.

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Sensory neuron addition in juvenile rat: Time course and specificity

Cited by 28 publications

References 48 publications

Primary Sensory Neuron Addition in the Adult Rat Trigeminal Ganglion: Evidence for Neural Crest Glio-Neuronal Precursor Maturation

Primary Sensory Neuron Addition in the Adult Rat Trigeminal Ganglion: Evidence for Neural Crest Glio-Neuronal Precursor Maturation

Effects of systemically administered NT‐3 on sensory neuron loss and nestin expression following axotomy

Trust, but verify: The necessity of empirical verification in quantitative neurobiology

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