Target specificity and size of avian sensory neurons supported in vitro by nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3.
To obtain insight into which subpopulations of sensory neurons in dorsal root ganglia are supported by different neurotrophins, we retrogradely labeled cutaneous and muscle afferents in embryonic day 9 chick embryos and followed their survival in neuron-enriched cultures supplemented with either nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), or neurotrophin-3 (NT-3). We found that NGF is a wide survival factor for subpopulations of both cutaneous and muscle afferents, whereas the survival effects of BDNF and NT-3 are restricted primarily to muscle afferents. We also measured soma size in each neurotrophic factor. These new data show that BDNF- and NT-3-dependent cells appear to be a mixture of two populations of neurons: one small diameter and the other large diameter. In contrast, based on size alone, NGF-dependent cells appear to be a single population of only small-diameter neurons. Thus, BDNF and NT-3 may have some new, previously unreported effects on small-diameter afferent neurons.
LoPresti
P
P
Department of Neurobiology and Behavior, State University of New York at Stony Brook 11794.
Scott
S A
SA
D000818:Animals; D019208:Brain-Derived Neurotrophic Factor; D002232:Carbocyanines; D016923:Cell Death; D002642:Chick Embryo; D005727:Ganglia, Spinal / Q000187:drug effects*; D009132:Muscles / Q000294:innervation*; D009414:Nerve Growth Factors / Q000235:genetics / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009475:Neurons, Afferent / Q000187:drug effects*; D020933:Neurotrophin 3; D012867:Skin / Q000294:innervation*
C035005:3,3'-dihexadecylindocarbocyanine; D019208:Brain-Derived Neurotrophic Factor; D002232:Carbocyanines; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D020933:Neurotrophin 3