Involvement of renal nerves and endothelins in the regulation of renal water excretion in diabetes insipidus rats.
The interaction between renal nerves, endothelins acting via endothelin-A receptors and vasopressin in the regulation of renal excretory function was investigated. In conscious intact and renal denervated diabetes insipidus (DI) Brattleboro rats, as well as their controls, Long-Evans (LE) rats, an infusion of 16.4 nmol/kg/min ET(A) receptor antagonist BQ-123 was performed in the course of 50 min. Femoral artery blood pressure, heart rate, Ccr, V x U(Na), V x U(K) and V x U(Cl) did not alter in any of the groups. Urine flow rate diminished by 38.1% (p < 0.02), while urine osmolality increased by 30.3% (p < 0.05) as a result of BQ-123 infusion in the intact LE rats but neither urine flow rate nor urine osmolality changed in the DI rats. In contrast to intact LE rats, BQ-123 infusion in renal denervated LE rats did not alter urine flow rate or urine osmolality. However, urine flow rate in renal denervated DI rats surprisingly decreased by 71.1% (p < 0.01) while urine osmolality increased by 161% (p < 0.001) as a result of BQ-123 infusion. Endogenous endothelins can regulate renal water excretion through ET(A) receptor activation. Renal sympathetic nerves participate in the modulation of renal water excretion influencing the ET(A) receptor-mediated effects of endothelins in the kidney.
Girchev
R
R
Department of Physiology, Medical University, Sofia, Bulgaria. girchev@medfac.acad.bg
Markova
P
P
Mikhov
D
D
Avramova
T
T
Nattcheff
N
N
D000818:Animals; D001794:Blood Pressure; D003714:Denervation; D003919:Diabetes Insipidus / Q000378:metabolism / Q000503:physiopathology*; D016232:Endothelins / Q000502:physiology*; D006339:Heart Rate; D007668:Kidney / Q000294:innervation* / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D014867:Water / Q000378:metabolism
D016232:Endothelins; D014867:Water