title: Effects of nonpeptide vasopressin V2 antagonist tolvaptan in rats with heart failure.
abstract: Similar to other neurohormones that are activated in chronic heart failure (CHF), circulating arginine vasopressin (AVP) is elevated in patients with CHF. The precise role of AVP in the pathophysiology of cardiovascular disease is controversial. AVP is a peptide hormone that contributes to water retention and vasoconstriction in CHF through effects on V(2) and V(1a) receptors, respectively. In the present study, the effect of V(2) receptor (V(2)R) blockade using tolvaptan was assessed in a rat model of myosin-induced experimental autoimmune myocarditis. CHF was elicited in Lewis rats by immunization with porcine cardiac myosin, and 28 days after immunization rats were treated for 28 days with oral tolvaptan (3 or 10mg/(kg day)) or vehicle. CHF was characterized by left ventricular remodeling and impaired systolic and diastolic function. Chronic V(2)R blockade increased urine volume and urinary AVP excretion and decreased urine osmolality but had no natriuretic effect, and as a result caused increases in plasma osmolality and sodium. High doses of tolvaptan markedly elevated electrolyte-free water clearance. V(2)R blockade did not activate the renin-angiotensin system, not influence cardiac remodeling, cardiac function, or survival. The upregulation of aquaporin 2 protein in the kidney of CHF rats was inhibited by the administration of V(2)R antagonist. These results suggest that in a rat model of CHF, AVP plays a major role in water retention through the renal V(2)R.
authors.affiliation: Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashizima, Niigata city 956-8603, Japan.
authors.forename: Punniyakoti T
authors.initials: PT
authors.lastname: Veeraveedu
authors.forename: Kenichi
authors.initials: K
authors.lastname: Watanabe
authors.forename: Meilei
authors.initials: M
authors.lastname: Ma
authors.forename: Suresh S
authors.initials: SS
authors.lastname: Palaniyandi
authors.forename: Ken'ichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Makoto
authors.initials: M
authors.lastname: Kodama
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
mesh_terms: D000450:Aldosterone / Q000097:blood; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D051399:Aquaporin 2 / Q000378:metabolism; D001127:Arginine Vasopressin / Q000652:urine; D001552:Benzazepines / Q000627:therapeutic use*; D024722:Cardiac Myosins; D004232:Diuretics / Q000627:therapeutic use*; D006321:Heart / Q000254:growth & development / Q000503:physiopathology; D006333:Heart Failure / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D006439:Hemodynamics / Q000187:drug effects; D007668:Kidney / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D009994:Osmolar Concentration; D051381:Rats; D011917:Rats, Inbred Lew; D012964:Sodium / Q000097:blood; D000077602:Tolvaptan
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D001552:Benzazepines; D004232:Diuretics; D001127:Arginine Vasopressin; D000077602:Tolvaptan; D000450:Aldosterone; D012964:Sodium; D024722:Cardiac Myosins