Corneal innervation and sensitivity to noxious stimuli in trkA knockout mice

摘要: Most primary sensory neurones depend on neurotrophins for survival. Mutant mice in which TrkA, the high-affinity receptor nerve growth factor (NGF), has been inactivated lack nociceptive ganglia and do not respond to noxious stimuli. The cornea of eye is innervated by trigeminal that are activated mechanical, thermal chemical In human cornea, these stimuli evoke only sensations pain. We have analysed innervation pattern response stimulation trkA (-/-) mutant mice. Corneal nerves were stained with gold chloride impregnation method. sensitivity was assessed counting blinking movements evoked von Frey hairs, topical application saline at different temperatures acetic acid capsaicin concentrations. animals, we observed a drastic reduction number trunks branches corneal stroma. Furthermore, quantitative analysis thin terminals revealed marked decrease epithelium when compared those present wild type (+/-) animals. also significantly reduced. These results indicate population markedly depleted However, small portion survive suggesting they may be NGF independent. On basis our results, propose surviving cells polymodal neurones, sensitive mechanical stimulation, heat acid.