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

This study was designed to determine the expression and localization of the alpha-adrenoceptor (AR) subtypes in human ureteral tissue. The expression of the alpha-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 alpha-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 alpha-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, alpha-1D high expression percentage was significantly higher than alpha-1A and -1B subtype (80, 10, 20, and 90, 20, 10%, respectively). In the distal ureter, alpha-1D expression was higher than alpha-1A and -1B subtype but there was no statistical significance (100, 80, 70%). The distal ureter had higher density of alpha-AR receptors than proximal and mid ureter. The expression of alpha-1A and alpha-1B AR in distal ureter was significantly higher than proximal and mid ureter. alpha-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 alpha-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.