Abstract
Purpose: :
Transient receptor potential (TRP) is a superfamily of cation channels permeable to calcium. It is activated by a wide range of stimuli such as heat (>43°C), low pH (<6.5), hypoxia, hypertonicity, etc. TRPV1 receptor expression in the visual system has been localized in the epithelium and endothelium of the cornea, in the ophthalmic branch of the trigeminal nerve and in the developing retina. Our aim was to demonstrate the expression of this receptor in the whole eye.
Methods: :
Thirteen New Zealand White adult rabbits of approximately 2 Kg were used in this study and five human eyes obtained from the pathology department. Antibodies anti-human TRPV1 rabbit polyclonal antibody, anti-rabbit TRPV1 sheep polyclonal antibody and vimentine monoclonal antibody were used.Total RNA was isolated from the following ocular structures: lacrimal gland, ciliary body, retina and lens. Real time PCR was performed using StepOnePlus detection system. The following gene-specific probes and primers available as Taqman assays were used: Oc03397394_m1 (TRPV1) and 824823 B3 (HPRT1)
Results: :
TRPV1 protein was found in the corneal epithelium and endothelium and in the basal layer of the conjunctiva. TRPV1 protein was also found in the epithelia of the ciliary body, in the pars plana and plicata and epithelium of lens. In the retina, the retinal pigmented epithelium and Müller cells in the inner layer of the structure were found positive for this protein. At the mRNA level, TRPV1 was found in the lacrimal gland, retina, ciliary body, lens and cornea. The highest expression was found in the lens, whereas the lowest levels were found in the retina.
Conclusions: :
The specific cell localization of TRPV1 in the epithelia and Müller cell colocalizes with places very actively involved in exchange of ions and water flow in the eye, thus a role of TRPV1 as osmosensor channel could be expected in this particular cells.
Keywords: ion channels • cell membrane/membrane specializations • calcium