Abstract
Purpose :
To determine if synaptic vesicle proteins are present in nerve fibers of the rat corneal epithelium. This could provide targets for therapeutic treatment of chronic corneal pain conditions such as Recurrent Corneal Erosion or Corneal Neuropathy.
Methods :
- Twelve naïve rats were perfused transcardially using fixative (0.8% picric acid, 0.2% paraformaldehyde) and the left and right corneas were collected.
- Whole mounts of the cornea were prepared for immunohistochemistry with rabbit antisera for β-Tubulin III and mouse antisera for Synaptotagmin (Mab30, Mab48), Syntaxin-1, SNAP-25, and Synaptobrevin, as well as mouse antisera for β-Tubulin III and rabbit antisera for Rab3D, Synapsin-1, Synapsin-1 P-Ser9, and N-ethylmaleimide sensitive fusion protein (NSF).
- A Leica confocal microscope was used to visualize nerve fibers with β-Tubulin III and synaptic proteins.
Results :
Varicose nerve fibers (β-tubulin III) were present in both the epithelium and stroma of the cornea. These nerve fibers contained the synaptic proteins Synaptotagmin, SNAP-25, Synaptobrevin, Synapsin-1, Rab3D.
Conclusions :
The synaptic proteins Synaptotagmin, SNAP-25, Synaptobrevin, Synapsin-1, and Rab3D were labeled in both the intraepithelial and stromal nerve fibers of the rat cornea. This indicates that glutamate is synaptically released from sensory nerve fibers of the cornea. When released, glutamate could activate and sensitize nerve fibers in an autocrine or paracrine fashion. Understanding of this mechanism may be useful in the treatment of corneal pain due to recurrent corneal erosion or corneal neuropathies.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.