Alpha 1B-adrenergic receptors in rat renal microvessels. Kidney Int 1995 Nov;48(5):1412-9
Date
11/01/1995Pubmed ID
8544397DOI
10.1038/ki.1995.430Scopus ID
2-s2.0-0028876235 (requires institutional sign-in at Scopus site) 8 CitationsAbstract
Although several alpha-adrenergic receptor genes are expressed in the rat kidney, their expression in the renal vasculature has not been studied. Since pharmacological studies have suggested that an alpha 1B-adrenergic receptor may mediate renal vasoconstriction, we studied the expression of alpha 1B-adrenergic receptors in renal microvessels, from 10- to 14-week-old male spontaneously hypertensive rats (SHR) and their normotensive control, the Wistar-Kyoto rat (WKY). In these microvessels, isolated by perfusion with iron, alpha 1B-adrenergic receptor mRNA levels (by ribonuclease protection assay) were similar in SHR and WKY rats. Photo-affinity labeling with [125I]-arylazidoprazosin demonstrated the presence of alpha 1B-adrenergic receptor protein. Maximum receptor density (determined by 3H-prazosin binding: Bmax 59.8 +/- 4.1 and 58.7 +/- 4.3; Kd 0.48 +/- 0.05 nM and 0.31 +/- 0.06 nM in SHR and WKY, respectively) and chloroethylclonidine (CEC)-sensitive binding sites (determined by [125I]-(2-beta(4-hydroxyphenyl)-ethylaminomethyl)-tetralone binding) (125I-HEAT) were similar in SHR and WKY rats. There are two novel findings in these studies: (1) the alpha 1B-adrenergic receptor gene is expressed in renal microvessels of WKY and SHR; (2) alpha 1B-adrenergic receptor gene expression in renal microvessels is not altered in adult SHR. The failure to down-regulate expression of the alpha 1B-adrenergic receptor at the mRNA and protein level in the SHR could result in persistence of alpha 1B-adrenergic receptor effects and contribute to the increased vascular resistance in hypertension.
Author List
Canessa LM, Piccio MM, Vachvanichsanong P, Sidhu A, Porter CC, Robillard JE, Felder RA, Jose PAMESH terms used to index this publication - Major topics in bold
Affinity LabelsAlkylating Agents
Animals
Azides
Binding Sites
Blood Vessels
Clonidine
Male
Microcirculation
Prazosin
RNA, Messenger
Radioligand Assay
Rats
Rats, Inbred SHR
Rats, Inbred WKY
Receptors, Adrenergic, alpha
Renal Circulation
