TRKA, TRKB AND P75 MESSENGER-RNA EXPRESSION IS DEVELOPMENTALLY-REGULATED IN THE RAT RETINA

We examined the cellular distribution of mRNAs coding for the neurotro phin receptors TrkA, TrkB and p75 in the rat retina during early postn atal development. At PO (postnatal day 0), mRNAs coding for each of th e three receptors were detected in the ganglion cell layer (GCL) and i n the inner plexiform layer (IPL), the latter structure essentially co ntaining retinal ganglion cell processes at this developmental stage. At P5, the innermost part of the inner nuclear layer (INL) also expres sed TrkA, TrkB and p75 mRNAs. Finally, the GCL, IPL and the whole INL of P10 retinae were labeled by the three probes. The developmentally r egulated expression of these receptors underlies a possible role for n eurotrophins in the differentiation and survival of retinal cells.