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Ontogeny of DA1 receptor-mediated natriuresis in the rat: in vivo and in vitro correlations.
- Source :
-
The American journal of physiology [Am J Physiol] 1992 Sep; Vol. 263 (3 Pt 2), pp. R631-8. - Publication Year :
- 1992
-
Abstract
- The natriuretic and diuretic effects of dopamine are attenuated in the young. Because dopamine has actions on receptors (e.g., adrenergic, serotonin) other than dopamine, we studied a novel dopamine agonist, pramipexole, which has a selectivity to both DA1 and DA2-receptor subtypes. Intravenous administration of pramipexole resulted in a dose-related (1, 10, and 100 micrograms.kg-1.min-1) increase in urine flow and absolute and fractional sodium excretion and a decrease in mean arterial pressure (MAP) in three groups of rats studied. Pramipexole induced a greater decrease in MAP in 6- to 7- (n = 5) and 9- to 16- (n = 6) than in 3- to 4-wk-old (n = 8) rats; the natriuresis and diuresis were greatest in 12- to 16- and least in 3- to 4-wk-old rats. The renal effects of pramipexole were mainly due to actions at the DA1 receptor, since these effects were completely blocked by the coinfusion of a DA1 antagonist, SKF 83742. To explore further a cause of the attenuated natriuretic effect of pramipexole in the young, we studied the effect of a selective DA1-receptor agonist, fenoldopam, on amiloride-sensitive 22Na+ uptake in renal brush-border membrane vesicles. The 3-s amiloride-sensitive uptake was inhibited (45%) by fenoldopam (5 x 10(-5)M) in 9- to 16- (n = 6) but not in 3- to 4-wk-old (n = 5) rats. These studies suggest that the attenuated natriuretic effect of dopamine in the young is in part due to decreased DA1 action on the brush-border membrane Na(+)-H+ exchanger.
- Subjects :
- Animals
Animals, Newborn
Benzothiazoles
Blood Pressure drug effects
Dopamine pharmacology
Dopamine Agents pharmacology
Dose-Response Relationship, Drug
Glomerular Filtration Rate drug effects
Hemodynamics drug effects
Kidney drug effects
Male
Pramipexole
Rats
Rats, Wistar
Thiazoles pharmacology
Time Factors
Aging urine
Natriuresis drug effects
Receptors, Dopamine D1 physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 263
- Issue :
- 3 Pt 2
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 1357983
- Full Text :
- https://doi.org/10.1152/ajpregu.1992.263.3.R631