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- Title
Alpha 1 adrenergic receptor control of renal blood vessels during aging.
- Authors
Passmore, John C.; Rowell, Peter P.; Joshua, Irving G.; Porter, James P.; Patel, Divyan H.; Falcone, Jeff C.
- Abstract
Aging humans and rats have a reduced renal vascular constriction response to stress, change in posture, or exercise. In this study, renal interlobar arteries from 9- (intermediate age) to 15-month-old (aging) male Wistar rats constricted less to alpha-adrenergic agonists than those of 4-month-old (young adult) rats. The reduced contraction to A61603 (alpha 1 A agonist) was similar to that to norepinephrine and phenylephrine. Therefore, it appears that the reduction in constriction is primarily related to alpha 1 A receptor stimulation. GeneChip microarray hybridization analysis of the interlobar arteries with the RAE 230A GeneChip indicated that there were no significant differences in gene expression for alpha 1 A/C, 1B, or 1D receptors between 4-month-old (young adult) and 1-year-old (aging) male Wistar rats. Competitive binding experiments (prazosin) revealed that maximal binding (Bmax, fmol/mg protein) of the alpha 1 receptors of interlobar arteries was reduced 25% by 10 months of age and 50% by 18+ months of age. Alpha 1 receptor-induced arterial constriction and prazosin binding were both down-regulated. The loss of receptor-initiated constriction likely includes down-regulation of maximum agonist binding by alpha 1 adrenergic receptors.
- Subjects
KIDNEYS; PHYSIOLOGICAL stress; BLOOD flow; ALPHA adrenoceptors; PRAZOSIN
- Publication
Canadian Journal of Physiology & Pharmacology, 2005, Vol 83, Issue 4, p335
- ISSN
0008-4212
- Publication type
Article
- DOI
10.1139/Y05-015