Intracellular calcium regulates the survival of early sensory neurons before they become dependent on neurotrophic factors.
To investigate the role of intracellular Ca2+ in the survival of developing neurons before they become neurotrophic factor dependent, we have studied chick embryo nodose neurons, which have a particularly protracted period of neuorophic factor independence. Pharmacological reduction of intracellular free Ca2+ or depletion of either Ca(2+)-regulated or inositol trisphosphate-regulated intracellular Ca2+ stores kills early neurotrophic factor-independent neurons, but has a negligible effect on older neurons growing in the presence of brain-derived neutrotrophic factor. Shortly before they become dependent on brain-derived neurotrophic factor, nodose neurons express L-type Ca2+ channels and their survival can be enhanced by depolarization-induced Ca2+ influx. We conclude that intracellular Ca2+ plays a role in regulating neuronal survival both prior to and after the onset of neurotrophic factor dependence, but does not mediate the survival-promoting effects of neurotrophic factors.
Larmet
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Y
Department of Anatomy, St. George's Hospital Medical School, Tooting, London, England.
Dolphin
A C
AC
Davies
A M
AM
D000818:Animals; D019208:Brain-Derived Neurotrophic Factor; D002118:Calcium / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D003470:Culture Media; D003600:Cytosol / Q000378:metabolism; D004553:Electric Conductivity; D005110:Extracellular Space / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism*; D007477:Ions; D009414:Nerve Growth Factors / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000494:pharmacology / Q000502:physiology*; D009475:Neurons, Afferent / Q000378:metabolism*; D009620:Nodose Ganglion / Q000166:cytology / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D013997:Time Factors
D019208:Brain-Derived Neurotrophic Factor; D003470:Culture Media; D007477:Ions; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D011188:Potassium; D002118:Calcium