Over-expression of NGF in skin causes formation of novel sympathetic projections to trkA-positive sensory neurons.
Previous studies have shown that transgenic mice over-expressing NGF in the skin have novel sympathetic 'basket-like' projections to sensory neurons similar to that seen in models of chronic pain. Since only a subset of sensory neurons in the NGF-transgenic mice received the sympathetic projections, we hypothesized that sympathetic sprouting was targeted to those neurons affected by increased levels of NGF. To test this, double-label immunohistochemistry for the NGF receptor (trkA) and sympathetic baskets was performed. Thirty-nine percent of all neurons in transgenic trigeminal ganglia were trkA-positive. Moreover, of the population of sensory neurons that received sympathetic input, 84% were trkA-positive. These results indicate that retrogradely transported NGF can induce and direct growth of sympathetic axons in vivo.
Davis
B M
BM
Department of Anatomy, University of Kentucky College of Medicine, Lexington 40536-0084, USA.
Goodness
T P
TP
Soria
A
A
Albers
K M
KM
D000818:Animals; D005728:Ganglia, Sympathetic / Q000187:drug effects* / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D009414:Nerve Growth Factors / Q000096:biosynthesis*; D009434:Neural Pathways / Q000187:drug effects; D009475:Neurons, Afferent / Q000737:chemistry*; D020917:Receptor, trkA / Q000032:analysis*; D012867:Skin / Q000187:drug effects* / Q000294:innervation; D012668:Trigeminal Ganglion / Q000187:drug effects / Q000378:metabolism
D009414:Nerve Growth Factors; D020917:Receptor, trkA