Abstract
Sairei-to (TJ-114), a traditional Japanese medicine, has been used clinically for the treatment of various edematous disorders. The inhibitory effect of TJ-114 on edema may be dependent on the diuretic response it invokes. The present study was performed to determine the effect of TJ-114 on the anti-diuretic hormone vasopressin, which is implicated in the retention of water in various edematous disorders. TJ-114 (0.5-1.5 g/kg) was administered intra-duodenally to pentobarbital-anesthetized rats. Specimens of the renal cortex were isolated 30min after the administration and incubated in buffered Hank's balanced salt solution with vasopressin. The vasopressin-stimulated cAMP production was dose-dependently attenuated in renal tissues in rats treated with TJ-114. The inhibitory effect of TJ-114 was diminished by pre-treatment with NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor. Therefore, TJ-114 may inhibit stimulation of the vasopressin V2 receptor which is closely related to nitric oxide production.
