Brain-derived neurotrophic factor exerts antinociceptive effects by reducing excitability of colon-projecting dorsal root ganglion neurons in the colorectal distention-evoked visceral pain model.

The mechanism underlying visceral pain is still largely unclear. Recently, much attention has focused on a potential modulatory role of brain-derived neurotrophic factor (BDNF) in visceral pain. In the present study, we investigated the expression of BDNF in dorsal root ganglia (DRG) primary sensory neurons and its role in a colorectal distention (CRD)-induced model of visceral pain. Results obtained from enzyme-linked immunosorbant assay (ELISA) revealed that BDNF protein was upregulated after CRD. An abdominal withdrawal reflex (AWR) assay confirmed that BDNF played an antinociceptive role in this model. Application of BDNF directly to DRG neurons decreased their hypersensitivity when evoked by CRD. Pretreatment with k252a partially blocked the effect of BDNF. These findings suggest that BDNF might be a novel analgesic agent for the treatment of visceral pain.