Purchase this article with an account.
T. M. Curtis, J. McKee, D. P. Dash, A. Arora, C. N. Scholfield, J. G. McGeown, D. A. Simpson; Expression of Transient Receptor Potential Channels in Retinal Arterioles. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2264.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Mammalian transient receptor potential (TRP) channels form a novel cation channel family consisting of nearly 30 members. Recent studies have suggested that these channels may play a pivotal role in controlling vascular contractility and permeability. In the present study we sought to identify systematically the TRP channel subtypes expressed in rat retinal arterioles.
Adult male Sprague-Dawley rats were anaesthetized with CO2 and killed by cervical dislocation. Retinas were removed and intact arteriole segments isolated. TRP channel mRNA expression was evaluated by RT-PCR, and rat brain and kidney samples were used as positive controls. Immunofluorescence staining with commercially available polyclonal antibodies was also used to test for cell-specific expression of TRP channels in retinal arterioles embedded within retinal flatmount preparations. Retinas were counter-stained with propidium iodide nuclear stain. The specificity of the antibodies was investigated by parallel control experiments in the absence of primary antibody.
With RT-PCR, mRNA of 13 TRP channel subtypes was detected in retinal arterioles: TRPC1, TRPC3, TRPC4, TRPC7, TRPV1, TRPV2, TRPV4, TRPM1, TRPM2, TRPM3, TRPM7, TRPML1 and TRPML3. Lack of expression of other TRP channels could not be attributed to RT-PCR conditions since all of the other TRP channel family members could be detected in brain or kidney. Immunofluorescence labelling revealed a punctuate distribution of TRPV2 throughout the vascular smooth muscle cell layer of retinal arterioles, while TRPV4 was specifically localised to the plasma membrane of endothelial cells. Consistent with the RT-PCR results, TRPC5 protein could not be detected in retinal arterioles. This was not due to a lack of antibody reactivity because intense staining was observed in the ganglion cell layer of the retina.
Our results indicate that multiple TRP channels are expressed in retinal arterioles. These data may serve as molecular basis for future work exploring the physiological significance of non-selective cation channels in the retinal vasculature.
This PDF is available to Subscribers Only