Expression of Renal α1 - Adrenergic Receptor Subtypes in Established Hypertension

Publisher Website
Google Scholar
Abstract
Summary: Radioligand binding studies were undertaken in renal membranes of normotensive and hypertensive rats in order to test the hypothesis that there are alterations in renal α1-adrenergic subtypes of genetic hypertensive animals. The highly selective competitive compound, ( + )-niguldipine, was used to distinguish high-affinity (α1a) from low-affinity (α1b) sites, after initial studies demonstrated that this compound had greater selectivity than 5-methylurapidil in distinguishing ala and alb sites in rat renal membranes. In contrast to the significant difference in the blood pressure of the spontaneously hypertensive rats (ΔBP = 74 mm Hg), there was no difference in the renal α1-adrenergic receptor density. Membranes from the whole kidneys of spontaneously hypertensive rats (SHRs) possessed 31% α1a and 69% α1b sites with -log(Ki) values of 10.0 ± 0.3 and 7.1 ±0.1, respectively, for ( + )-niguldipine. However, these values were not different from those obtained from renal membranes of the normotensive Wistar-Kyoto (WKY) rats. These results indicate that in spite of the elevated blood pressure during the established phase of hypertension, the number, the affinity, and the ratio of the α1a and αlb appear not to be responsible for the manifestation of hypertension during this phase.

This publication has 0 references indexed in Scilit: