title: Nerve growth factor supply for sensory neurons: site of origin and competition with the sympathetic nervous system.
abstract: Nerve growth factor (NGF) levels in the sensory nervous system were measured by a highly sensitive two-site enzyme immunoassay for NGF. Dorsal root ganglia and the adjacent spinal nerves contained 2.8 +/- 0.3 and 1.7 +/- 0.4 ng NGF/g wet wt., respectively, whereas no NGF was detectable in dorsal roots and spinal cord (less than 0.05 ng NGF/g wet wt.). It is concluded that sensory neurons are supplied with NGF exclusively from their peripheral and not from their central field of projection. Two days after treatment with 6-hydroxydopamine, which destroys sympathetic nerve terminals and thereby prevents the removal of NGF by sympathetic neurons, the NGF content of dorsal root ganglia and trigeminal ganglia increased to 285% and 161% of control, respectively. This indicates that in peripheral target tissues sensory and sympathetic neurons compete for NGF.
mesh_terms: D000818:Animals; D005260:Female; D005727:Ganglia, Spinal / Q000032:analysis; D008297:Male; D009414:Nerve Growth Factors / Q000032:analysis* / Q000378:metabolism; D009475:Neurons, Afferent / Q000032:analysis / Q000378:metabolism; D010525:Peripheral Nerves / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000032:analysis; D013126:Spinal Nerve Roots / Q000032:analysis; D013564:Sympathetic Nervous System / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000032:analysis
chemical_list: D009414:Nerve Growth Factors