Localizations and expressions of α-1A, α-1B and α-1D adrenoceptors in human ureter

Abstract

This study was designed to determine the expression and localization of the α-adrenoceptor (AR) subtypes in human ureteral tissue. The expression of the α-AR subtypes was examined by immunohistochemistry using subtype selective antibodies in proximal, mid and distal ureter. Ureter samples were obtained from pathological specimens of nephroureterectomy. A single pathologist scored the expression of receptor (grade 0, no staining; grade 1, 0–25% cells positive; grade 2, 26–50% cells positive; and grade 3, greater than 50%). We compared the mean grades of α-AR 1A, 1B and 1D and the percentage of receptor expression with grade 2 or more between receptor subtypes in each ureter level. The expression levels of all three subtypes are altered according to the level of ureter. In the proximal ureter, the mean grades of the α-1A, -1B and -1D receptors were 1.0 ± 0.5, 1.1 ± 0.6, and 2.1 ± 0.7. Corresponding grades in the mid and distal ureter were 1.1 ± 0.6, 0.8 ± 0.6 and 2.0 ± 0.8, and 2.0 ± 0.7, 1.8 ± 0.6 and 2.5 ± 0.5, respectively. When compared with percentage of high expression, in the proximal and mid ureter, α-1D high expression percentage was significantly higher than α-1A and -1B subtype (80, 10, 20, and 90, 20, 10%, respectively). In the distal ureter, α-1D expression was higher than α-1A and -1B subtype but there was no statistical significance (100, 80, 70%). The distal ureter had higher density of α-AR receptors than proximal and mid ureter. The expression of α-1A and α-1B AR in distal ureter was significantly higher than proximal and mid ureter. α-1D expression in distal ureter was also higher than proximal and mid ureter but was not statistically significant (p = 0.28, 0.19, respectively). Our results show that α-1A, -1B and -1D AR subtypes are localized in human ureter irrespective of location. The expression levels of subtypes are altered according to level of ureter and subtype.