PAIN-RECEPTIVE NEURONS: IS TRK A TRACK?
Combining electrophysiological and immunocytochemical techniques, Fang’s research group showed that in the rat dorsal root ganglion (DRG) TrkA was highly expressed only in nociceptive neurons (TrkA is espressed in nociceptive neurons and influences electrophysiological properties via Nav1.8 expression in rapidly conducting nociceptors. J. Neurosci. 25, 4868-4878, 2005). They could find only a weak TrkA expression in some low-threshold mechanoreceptors.
This high intensity of expression was present in both fast-conducting and slow-conducting nociceptors.
The finding that a high expression of TrkA receptor is specific to pain-neurons provides a useful tool for the future identification of this cell type.