Enhanced responsiveness to CNS-induced natriuresis in anesthetized nonascitic cirrhotic rats.
Central nervous system (CNS)-induced natriuresis was investigated in nonascitic rats with CCl4-induced cirrhosis (CTC rats) under pentobarbital anesthesia. At baseline, urine sodium output (UNa+V, in mumol.min-1.100 g body wt-1) (-30%, P less than 0.01) and mean arterial pressure (MAP, in mmHg) (-12%, P less than 0.001) were significantly reduced in CTC rats (n = 32) compared with matched controls (n = 34). In response to intracerebroventricular infusion of sodium-rich (349 mM) artificial cerebrospinal fluid (Na(+)-CSF infusion), UNa+V was significantly higher in CTC rats (2.8 +/- 0.3; n = 15) than in controls (1.7 +/- 0.2; n = 17; P less than 0.01); no differences were found in pressor changes (24 +/- 3 vs. 19 +/- 2). A similar but normal sodium CSF (150 mM) infusion did not influence UNa+V or MAP in any group (n = 12, both). In contrast, CTC rats (n = 5) showed, compared with controls (n = 5), significantly reduced natriuretic (UNa+V, 6.9 +/- 0.5 vs. 12.4 +/- 0.9; P less than 0.001) and pressor (+16 +/- 3 vs. +31 +/- 2; P less than 0.01) responses to an intravenous hypertonic sodium overload. Natriuresis induced by Na(+)-CSF infusion was related to increases in creatinine clearance (similar in both groups) and in fractional sodium excretion, which was significantly higher in CTC rats (5.90 +/- 0.15%) than in controls (3.65 +/- 0.14%; P less than 0.01). In summary, CNS-dependent efferent natriuretic mechanisms were preserved in CTC rats and were able to reverse renal tubular sodium retention in these animals. It is proposed that Na(+)-CSF infusion may be a useful tool for the study of renal sodium retention in experimental liver cirrhosis.
Colina
I
I
Department of Medicine, University of Navarra, Pamplona, Spain.
Quiroga
J
J
Guarner
F
F
Purroy
A
A
Prieto
J
J
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002252:Carbon Tetrachloride Poisoning / Q000503:physiopathology*; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D007263:Infusions, Parenteral; D008106:Liver Cirrhosis, Experimental / Q000503:physiopathology*; D008297:Male; D009318:Natriuresis; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D012462:Saline Solution, Hypertonic