Nerve growth factor regulates galanin and c-jun overexpression occurring in dorsal root ganglion cells after intravesical resiniferatoxin application.

Galanin and c-jun expression after a single bladder instillation of resiniferatoxin was studied by immunocytochemistry in L6 dorsal root ganglia (DRG) neurons of the rat. The role of nerve growth factor depletion in causing that effect was also investigated. Three days after instillation of a 100 nM resiniferatoxin solution a marked increase in the number of galanin and c-Jun immunoreactive DRG cells was evident bilaterally. The increments were still present at 8 days and disappeared 1 month after treatment. Systemic administration of nerve growth factor, 100 microg/kg, prevented both overexpressions. Results suggest that the changes induced in bladder sensory neurons by intravesical resiniferatoxin are due, at least in part, to the temporary deprivation of bladder-derived neurotrophic factors, namely nerve growth factor, in those neurons.