Non-TrkA-expressing small DRG neurons are lost in TrkA deficient mice.
J Neurosci
; 15(9): 5929-42, 1995 Sep.
Article
em En
| MEDLINE
| ID: mdl-7666178
ABSTRACT
Experiments over the past decade in which NGF/TrkA signaling has been abolished by antibodies or targeted gene mutations have shown that 70-85% of dorsal root ganglion (DRG) neurons require NGF for survival during development. There is consensus that many of the NGF-dependent neurons are small-diameter, peptidergic neurons subserving nociception. These neurons express the signaling receptor for NGF, TrkA. There is a major discrepancy, however, between the percentage of DRG neurons which require NGF for survival (70-85%) and percentage of DRG neurons expressing TrkA receptors (40-50%). The identity of these non-TrkA expressing, NGF-dependent neurons has not been established. A candidate group is a population of small DRG neurons with unmyelinated axons which bind BSI isolectins from the plant, Bandeiraea simplicifolia. We show here that most of these BSI-binding DRG neurons do not express TrkA in adult mice. However, in mutant mice in which NGF/TrkA signaling has been abolished by inactivation of the trkA gene, BSI-staining in the DRG and dorsal horn is completely eliminated. BSI-binding DRG cells are thus the first identified neuronal population in which cells do not express TrkA in maturity, but require NGF/TrkA signaling for survival during embryonic development. These neurons must either depend on NGF via a novel, indirect mechanism or alternatively, downregulate TrkA expression during development.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Receptor trkA
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Lectinas de Plantas
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Gânglios Espinais
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Neurônios
Idioma:
En
Ano de publicação:
1995
Tipo de documento:
Article