title: Impaired renal response to portal infusion of hypertonic saline in adriamycin-treated rats.
abstract: 1. The hepatorenal reflex plays an important role in water and salt homeostasis by matching renal excretion to gastrointestinal absorption. This homeostatic mechanism is impaired in nephrotic rats. The present study tested the hypothesis that, in nephrotic rats, the renal sodium excretion response to hypertonic saline infusion is impaired due to decreased sensitivity of the hepatoportal sodium-sensing mechanism. 2. The present study was performed in control and adriamycin (ADR)-induced nephrotic syndrome rats. After baseline data collection, urinary sodium (U(Na)V) and potassium (U(K)V) excretion responses were tested following continuous infusion of hypertonic NaCl solution (20 μL/min for 30 min) into either the femoral or mesenteric vein. A second series of experiments tested hepatic and renal nerve responses to continuous mesenteric vein infusion of hypertonic NaCl (10 μL/s for 30 s). 3. Compared with control rats, nephrotic rats displayed significantly lower baseline U(Na)V and U(K)V excretion. In control rats, mesenteric compared with femoral vein infusion of hypertonic NaCl produced a more rapid and greater increase in U(Na)V. In contrast, in nephrotic rats, femoral and mesenteric vein infusion caused similar increases in U(Na)V and the maximum increases in U(Na)V to either route of infusion were much lower in nephrotic than control rats. Furthermore, portal hypertonic saline infusion caused greater increases in hepatic nerve activity and greater decreases in renal nerve activity in control compared with nephrotic rats. 4. These data suggest that, in rats, adriamycin treatment decreases hepatoportal sodium-sensing sensitivity, leading to marked impairment of hepatorenal reflex responses, potentially contributing to salt and water retention.
authors.affiliation: Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Dusit
authors.initials: D
authors.lastname: Jirakulsomchok
authors.forename: Supitcha
authors.initials: S
authors.lastname: Napawachirahat
authors.forename: Narupon
authors.initials: N
authors.lastname: Kunbootsri
authors.forename: Tunda
authors.initials: T
authors.lastname: Suttitum
authors.forename: Panakaporn
authors.initials: P
authors.lastname: Wannanon
authors.forename: James Michael
authors.initials: JM
authors.lastname: Wyss
authors.forename: Sanya
authors.initials: S
authors.lastname: Roysommuti
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000009:adverse effects*; D004317:Doxorubicin / Q000009:adverse effects*; D007668:Kidney / Q000187:drug effects* / Q000503:physiopathology; D008099:Liver / Q000502:physiology; D008297:Male; D009318:Natriuresis / Q000187:drug effects* / Q000502:physiology; D011188:Potassium / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012462:Saline Solution, Hypertonic / Q000009:adverse effects; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology
chemical_list: D000903:Antibiotics, Antineoplastic; D012462:Saline Solution, Hypertonic; D004317:Doxorubicin; D011188:Potassium