Renal nerves in exaggerated water and sodium excretion by hypertrophied kidney of anesthetized rats
Szénási, G.; Kottra, G.; Bencsáth, P.; Takács, L.
American Journal of Physiology 254(1 Pt 2): F32-F37
1988
ISSN/ISBN: 0002-9513 PMID: 3337245 Document Number: 326034
The effect of acute renal denervation (RD) on water (V), sodium (UNaV), and potassium excretion (UKV) from the hypertrophied and control kidney was studied in 5-sec-butyl-5-ethyl-2-thiobarbituric acid (Inactin)-anesthetized male rats 7 days after unilateral nephrectomy (Nx) or sham operation (SNx). V, UNaV, and UKV from the hypertrophied kidney were similar before and after RD or sham RD. In contrast, in SNx rats, left RD resulted in an ipsilateral increase in V (from 2.76 .+-. 0.39 to 5.31 .+-. 0.99 .mu.l .cntdot. min-1 .cntdot. g-1), UNaV (from 109 .+-. 36 to 857 .+-. 331 nmol .cntdot. min-1 .cntdot. g-1), and UKV (from 144 .+-. 44 to 807 .+-. 130 nmol .cntdot. min-1 .cntdot. g-1; P < 0.05 in all cases). Moreover, renal parameters from the hypertrophied kidney, subjected to either RD or sham RD, were not different from values after RD in SNx rats (V: Nx, sham RD = 5.72 .+-. 1.10; Nx, RD = 5.23 .+-. 0.66; SNx, RD = 5.31 .+-. 0.99 .mu.l .cntdot. min-1 .cntdot. g-1; UNaV: Nx, sham RD = 896 .+-. 319; Nx, RD = 821 .+-. 262; SNx, RD = 857 .+-. 331 nmol .cntdot. min-1 .cntdot. g-1; UKV: Nx, sham RD = 782 .+-. 127; Nx, RD = 860 .+-. 82; SNx, RD = 807 .+-. 130 nmol .cntdot. min-1 .cntdot. g-1). In additional experiments, integrated renal nerve activity (RNA) to the kidney in Nx and SNx rats was 4.0 .+-. 0.3 and 10.7 .+-. 0.9 .mu.V (P < 0.05), respectively. The decrease in UNaV elicited by splanchnic nerve stimulation (10 V, 4 Hz, 1 ms) in volume-expanded rats was attenuated in hypertrophied kidneys compared with control (C = -3,019 .+-. 474, hypertrophied = -1,603 .+-. 326 nmol .cntdot. min-1 .cntdot. g-1; P < 0.05). It is concluded that both decreased RNA and attenuated effect to splanchnic nerve stimulation contribute to the lack of denervation phenomenon from hypertrophied kidneys of anesthetized rats.