Contribution of hepatic adenosine A1 receptors to renal dysfunction associated with acute liver injury in rats.
Acute liver injury is associated with renal insufficiency, whose mechanism may be related to activation of the hepatorenal reflex. We previously showed that intrahepatic adenosine is involved in activation of the hepatorenal reflex to restrict urine production in both healthy rats and in rats with cirrhosis. The aim of the present study was to test the hypothesis that activation of intrahepatic adenosine receptors is involved in the pathogenesis of the renal insufficiency seen in acute liver injury. Acute liver injury was induced by intraperitoneal injection of thioacetamide (TAA, 500 mg/kg) in rats. The animals were instrumented 24 hours later to monitor systemic, hepatic, and renal circulation and urine production. Severe liver injury developed following TAA insult, which was associated with renal insufficiency, as demonstrated by decreased (approximately 25%) renal arterial blood flow, a lower (approximately 30%) glomerular filtration rate, and decreased urine production. Further, the increase in urine production following volume expansion challenge was inhibited. Intraportal, but not intravenous, administration of a nonselective adenosine receptor antagonist, 8-phenyltheophylline, improved urine production. To specify receptor subtype, the effects of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, an adenosine A(1) receptor antagonist) and 3,7-dimethyl-1-propargylxanthine (DMPX, an adenosine A(2) receptor antagonist) were compared. Intraportal but not intravenous administration of DPCPX greatly improved impaired renal function induced by acute liver injury, and this beneficial effect was blunted in rats with liver denervation. In contrast, neither intraportal nor intravenous administration of DMPX showed significant improvement in renal function. In conclusion, an activated hepatorenal reflex, triggered by intrahepatic adenosine A(1) receptors, contributed to the pathogenesis of the water and sodium retention associated with acute liver injury.
Ming
Zhi
Z
Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada.
Fan
Yi-Jun
YJ
Yang
Xi
X
Lautt
W Wayne
WW
D058916:Adenosine A1 Receptor Antagonists; D058917:Adenosine A2 Receptor Antagonists; D000818:Animals; D056486:Chemical and Drug Induced Liver Injury; D003714:Denervation; D004195:Disease Models, Animal; D008099:Liver / Q000187:drug effects / Q000294:innervation; D008107:Liver Diseases / Q000150:complications*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D043683:Receptors, Adenosine A2 / Q000378:metabolism; D051437:Renal Insufficiency / Q000209:etiology / Q000503:physiopathology*; D012964:Sodium / Q000652:urine; D013805:Theobromine / Q000031:analogs & derivatives / Q000494:pharmacology; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D013853:Thioacetamide; D014556:Urine; D014970:Xanthines / Q000494:pharmacology*
D058916:Adenosine A1 Receptor Antagonists; D058917:Adenosine A2 Receptor Antagonists; D043682:Receptor, Adenosine A1; D043683:Receptors, Adenosine A2; D014970:Xanthines; D013853:Thioacetamide; C057837:3,7-dimethyl-1-propargylxanthine; D012964:Sodium; C051360:1,3-dipropyl-8-cyclopentylxanthine; D013806:Theophylline; C028322:8-phenyltheophylline; D013805:Theobromine