[Effects of a new vasodilator, budralazine on water drinking activity, plasma norepinephrine, plasma angiotensin II, plasma arginine vasopressin, plasma serotonin concentration, urinary aldosterone excretion rate and urinary catecholamine excretion rate in rats].

: Present study was undertaken to elucidate the effects of a new vasodilatating antihypertensive drug, budralazine on water drinking behavior and humoral factors including plasma norepinephrine (NE), angiotensin II (A II), arginine vasopressin (AVP), serotonin (5-HT) concentrations, urinary aldosterone and catecholamine excretion rates. After oral budralazine administration (10 mg/kg/day, p.o., for 7 days), systolic tail blood pressure of Wistar Kyoto rats (WKY) decreased significantly. While, heart rate and water drinking activity of WKY significantly increased. Urinary catecholamine excretion rate did not change after oral administration of budralazine (10 mg/kg and 100 mg/kg/day, p.o.; for 7 days). However, significant increase in urinary aldosterone excretion rate was demonstrated. Both plasma A II and NE concentrations tended to increase after oral administration of budralazine (100 mg/kg/day). Plasma AVP and 5-HT concentrations were not influenced by budralazine. These findings suggest that budralazine acts on renin angiotensin aldosterone system as compared to that in the sympathetic nervous system.