Abstract
Immunohistochemistry for tyrosine hydroxylase (TH) was performed on the dorsal root ganglia (DRG) in wild-type, heterozygous and Brn-3a knockout mice at embryonic day 18.5. TH-immunoreactive (-IR) neurons were detected in the DRG of wild-type and heterozygous mice, but their proportion was greatly increased by the loss of Brn-3a function (wild-type and heterozygot, 8.4%; knockout, 20.9%). IR neurons were of various sizes in wild-type (mean+/-S.D.=118.1+/-55.4 microm2, range=26.6-306.3 microm2) and heterozygous mice. In the knockout mice, however, TH-IR neurons were mostly small (mean+/-S.D.=68.2+/-34.3 microm2, range=11.8-166.8 microm2). The present study suggests that Brn-3a may normally suppress TH expression in many small DRG neurons but activate TH expression in large DRG neurons.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Calcitonin Gene-Related Peptide / metabolism
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Catecholamines / biosynthesis
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Cell Size
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DNA-Binding Proteins / genetics*
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Ganglia, Spinal / cytology
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Ganglia, Spinal / metabolism*
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Heterozygote
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Homozygote
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Mice
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Mice, Knockout
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Neurons, Afferent / cytology
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Neurons, Afferent / metabolism*
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Nociceptors / physiology
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Pain / metabolism
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Transcription Factor Brn-3
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Transcription Factor Brn-3A
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Transcription Factors / genetics*
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Tyrosine 3-Monooxygenase / metabolism*
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Up-Regulation / physiology*
Substances
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Catecholamines
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DNA-Binding Proteins
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Pou4f1 protein, mouse
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Transcription Factor Brn-3
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Transcription Factor Brn-3A
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Transcription Factors
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Tyrosine 3-Monooxygenase
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Calcitonin Gene-Related Peptide