IDENTIFICATION OF ALPHA(1C)-ADRENERGIC RECEPTOR MESSENGER-RNA IN BOVINE RETINAL-PIGMENT EPITHELIUM

Purpose. To examine the localization of a novel alpha1-adrenergic receptor subtype of alpha1C receptor in the eye, we compared the amount of alpha1C receptor transcripts in bovine retinal pigment epithelium (RPE) and in neural retina by employing reverse transcription of mRNA and the polymerase chain reaction (RT-PCR) assay. Methods. RT-PCR assay with specific primers for the alpha1C-adrenergic receptor and for beta-actin showed linear relationships between input quantity of RNA and the amount of amplified PCR products for the alpha1C-adrenergic receptor and also for beta-actin, when PCR was conducted for 24 and 15 cycles, respectively. Results. The RT-PCR assay demonstrated that the spontaneous expression level of the alpha1C-adrenergic receptor mRNA was much higher in bovine RPE than in neural retina; the alpha1C-adrenergic receptor/beta-actin ratio from RPE was 0.33 +/- 0.15 (n = 4), whereas that from neural retina was virtually zero. Conclusions. The RT-PCR assay is a sensitive semiquantitative method for a low abundance mRNA in a limited number of cells. Using the alpha1C receptor as a model, we demonstrated the usefulness of this assay by showing the uneven distribution of the alpha1C receptor transcripts in bovine RPE cells and neural retina.