Expression of mRNAs encoding full-length and truncated TrkB receptors in rat dorsal root ganglia and spinal cord following peripheral inflammation

PERIPHERAL inflammation induces an increased brain-derived neurotrophic factor (BDNF) synthesis in the dorsal root ganglion (DRG) and an elevated anterograde transport of BDNF to axon terminals in the spinal dorsal horn. To characterize whether expression of trkB is modulated in response to BDNF elevation in these areas, we evaluated changes in expression of full-length and truncated trkB (trkB.FL and trkB.T) mRNAs after injection of complete Freund's adjuvant into the hind paw of the rat. Reverse transcription- polymerase chain reaction analysis revealed that BDNF and trkB.T mRNAs levels in the DRG increased, while no change of expression of trkB.FL mRNA was observed. There was no detectable change in both trkB.FL and trkB.T mRNAs levels in the spinal cord. Considering that trkB.T mRNA is expressed mainly in the perineuronal satellite cells, these results suggest a possible paracrine role of BDNF within the DRG in addition to an important role related with nociception following peripheral inflammation.