Gene expression of P2X-receptors in the developing inner ear of the rat

Reverse transcription-polymerase chain reaction (RT-PCR) was used to characterize the expression of P2X receptor subunits (P2X 1-P2X 7) in different inner ear tissues. The present study revealed the presence of P2X 2, P2X 3, P2X 4 and P2X 7-mRNA in rat organ of Corti, vestibular organ and spiral ganglion at different postnatal developmental stages (PD1–PD16), with slight differences in the onset of expression. Expression of P2X 1, P2X 5 and P2X 6-mRNA was not detectable in the inner ear tissues. In addition, single cell RT-PCR experiments with outer hair cells (OHC) revealed the expression of either the P2X 2 or the P2X 2–2 splice variant or coexpression of both isoforms in individual cells. Our data suggest that extracellular adenosine-5’-triphosphate (ATP) may play an important role in signal transduction in the inner ear.