Neuroreport
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Levels of nerve growth factor (NGF) in rat hindpaw skin, measured with a sensitive two-site enzyme-linked immunosorbent assay, show two peaks during normal development. The first (57 +/- 5 pg mg-1) occurs at embryonic days (E) 18-20 and coincides with the arrival of axon terminals into the hindpaw skin. ⋯ Skin wounding at birth produces a marked increase in NGF levels (149 +/- 25 pg mg-1) which declines after 4 days. This large increase is not observed if wounding is performed at older ages and may underlie the sensory hyperinnervation that accompanies neonatal wounds.