Increased levels of TrkA in the regenerating retinal ganglion cells of fish

RETINAL ganglion cells of the fish have the spontaneous capacity to regener ate after nerve crush, a phenomenon known to be facilitated by nerve growth factor (NGF). We have studied the high-affinity NGF receptor TrkA, during the regeneration of the tench (Tinca tinca L.) optic nerve, using immunocyt ochemical techniques. TrkA-like immunoreactivity increased during the regen eration of the retinal ganglion cells. The increase is followed by a change in the subcellular distribution from perinuclear in control cells to cytop lasmic and perinuclear in regenerating ones. This increase was observed whe n antibodies against the extracellular domain of TrkA were used; no changes in TrkA-like immunoreactivity were observed with antibodies against the in tracellular domain of TrkA. We thus conclude that modulation of TrkA is inv olved in the regeneration of fish retinal ganglion cells. (C) 1998 Lippinco tt Williams & Wilkins.