Distribution of alpha-1 adrenoceptor subtypes in RNA and protein in rabbit eyes

1 We investigated subtypes of alpha-1 adrenoceptor (AR) in rabbit ocular tissues using reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and binding studies. 2 Competitive RT-PCR assays specific for the subtypes of alpha-1 AR revealed that the mRNA expression of alpha-la AR was dominant, and that of each alpha-1b and alpha-1d was less than 10% and 0.5% of total alpha-1 ARs mRNA. respectively, in the iris, ciliary body, choroid and retina. 3 In alpha-la AR splice isoform-specific RT-PCR assays, we found a distinct proportion of each isoform mRNA in the iris, ciliary body and choroid. 4 The results of the ISH assays for alpha-1a AR subtype showed that hybridization signals were clearly observed in the iris dilator muscle and in the epithelium of the ciliary processes. 5 In binding studies, alpha-1A AR was a dominant subtype in the iris, choroid and retina in contrast to the ciliary body that had more alpha-1B than alpha-1A AR subtype at protein level.