AJP - Renal Physiology, Vol 250, Issue 6 1033-F1038, Copyright © 1986 by American Physiological Society
Dopamine receptors modulate sodium excretion in denervated kidney
P. A. Jose, R. A. Felder, R. R. Holloway and G. M. Eisner
Dopamine (DA) modulates sodium excretion by the innervated kidney. To
examine the role of DA in the denervated (DNX) kidney the effects of the
DA1/DA2 antagonist cis-flupenthixol (group 2, n = 7) (10 nmol X kg-1 X
min-1), given intravenously in saline-loaded Wistar-Kyoto rats after acute
unilateral left DNX, were compared with a placebo group (group 1, n = 7)
and a group that received the DA1 antagonist SCH 23390 (group 3, n = 7) at
2.5 nmol X kg-1 X min-1. Pentobarbital sodium anesthesia was employed.
Adequacy of DNX was assessed by a natriuresis and decrease in renal
norepinephrine content in the DNX kidney and an antinatriuresis in the
innervated right kidney. Mean arterial pressure slightly decreased in the
placebo group (group 1, 106.7 +/- 2.2 vs. 99.3 +/- 2.4 mmHg) and after
cis-flupenthixol (group 2, 108.8 +/- 2.7 vs. 92.8 +/- 1.8 mmHg) but not
after SCH 23390 (group 3, 105.6 +/- 1.6 vs. 103 +/- 1.1 mmHg). Glomerular
filtration rate was not affected by placebo or SCH 23390 in the DNX or
innervated kidney but did slightly decrease after cis-flupenthixol in the
DNX kidney. Sodium and water excretion after drug administration differed
among the groups. In the DNX kidney urine flow decreased only in group 2,
whereas fractional sodium excretion decreased modestly (P less than 0.05
paired t test) with SCH 23390 (3.53 +/- 0.34 vs. 2.89 +/- 0.20%) markedly
with cis-flupenthixol (3.18 +/- 0.50 vs. 1.21 +/- 0.18%) and was unchanged
in the placebo group (3.25 +/- 0.61 vs. 3.45 +/- 0.45%).(ABSTRACT TRUNCATED
AT 250 WORDS)
