AN RT-PCR ANALYSIS OF MESSENGER-RNA FOR GROWTH-FACTOR RECEPTORS IN DAMAGED AND CONTROL SENSORY EPITHELIA OF RAT UTRICLES

Sensory epithelia from normal rat utricles and those cultured with and without neomycin treatment were assayed for the presence of growth fa ctor receptor mRNAs by RT-PCR (reverse transcriptase-polymerase chain reaction). Both undamaged and damaged utricles showed mRNA for Insulin receptor, IGF-I receptor, FGF receptor 1, EGF receptor, and PDGF alph a receptor. Neomycin-damaged sensory epithelia showed less PDGF alpha receptor mRNA than undamaged epithelia, suggesting that this message m ay be expressed at higher copy levels in hair cells than in supporting cells. Consistent with that hypothesis, immunohistochemistry revealed much stronger PDGF alpha receptor staining in the hair cells than in the supporting cells. Preliminary evidence suggests that IGF-I recepto r message also my be lowered in neomycin-damaged epithelia.