In vivo survival requirement of a subset of nodose ganglion neurons for nerve growth factor.
The sensory neurons of the nodose ganglion are the classic example of a population of peripheral nervous system neurons that do not require nerve growth factor (NGF) for survival during development but are dependent on other neurotrophins. We have re-examined this assertion by studying the development of the nodose ganglion of mice that have a null mutation in the NGF gene. Compared with wild-type embryos, the number of neurons undergoing apoptosis was elevated in NGF -/- mice, resulting in a significant reduction in the total number of neurons in the ganglion by the end of embryonic development. TrkA, the NGF receptor tyrosine kinase, was expressed in the nodose ganglion throughout development and there was a marked decrease in TrkA mRNA expression in the nodose ganglion of NGF -/- embryos. Although the in vitro survival of the majority of nodose neurons was promoted by brain-derived neurotrophic factor (BDNF), a minor proportion was supported by NGF in cultures established over a range of embryonic stages. These results clearly demonstrate that a subset of nodose ganglion neurons depends on NGF for survival during development. The finding that the expression of tyrosine hydroxylase (TH) mRNA was unaffected in the nodose ganglia of NGF-deficient embryos indicates that this NGF-dependent subset is distinct from the subset of catacholaminergic neurons in the nodose ganglion.
Forgie
A
A
School of Biomedical Sciences, Bute Medical Buildings, University of St Andrews, St. Andrews, Fife KY16 9AT, Scotland, UK.
Kuehnel
F
F
Wyatt
S
S
Davies
A M
AM
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D002470:Cell Survival; D002478:Cells, Cultured; D004790:Enzyme Induction; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D020932:Nerve Growth Factor / Q000172:deficiency / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009620:Nodose Ganglion / Q000166:cytology* / Q000196:embryology; D012333:RNA, Messenger / Q000096:biosynthesis; D020917:Receptor, trkA / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014446:Tyrosine 3-Monooxygenase / Q000096:biosynthesis / Q000235:genetics
D019208:Brain-Derived Neurotrophic Factor; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D020932:Nerve Growth Factor; D014446:Tyrosine 3-Monooxygenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D020917:Receptor, trkA