Expression and localization of angiotensin II type 1 receptor mRNA in rat ocular tissues.

Angiotensin II type 1 receptor (AT1) is expressed in a variety of tissues. However, the localization of the specific AT1 mRNA in several ocular tissues has not been fully elucidated. In the present study, we investigated the expression and distribution of AT1 mRNA in the several ocular tissues of Wistar-Kyoto rats (WKYs) using the technique of reverse transcription with polymerase chain reaction. The 5 cornea, sclera, iris, ciliary body, and choroid samples tested were negative. When we analyzed 5 retina samples, 4 were positive. AT1 mRNA was more significantly expressed in the retina of WKYs than in the other ocular tissues of WKYs (p = 0.0238 < 0.05). Our study provides the first direct evidence that the AT1 is abundantly present in the WKY retina portions. This is a strategic location for an ocular renin-angiotensin system to influence retinal cicrulation.