Inhibitory effects of Hachimijiogan on micturition reflex via the locus coeruleus

Abstract

Pharmacological studies were undertaken to elucidate the role of Hachimijiogan in the micturition reflex via the locus coeruleus, using a-chloralose-anesthetized cats. Rhythmic contractions of the urinary bladder induced by continuous infusion of saline into the bladder were dose-dependently inhibited by intravenous injection of Hachimijiogan (10, 30 and 90 mg/kg), as well as flavoxate hydrochloride (1 and 3 mg/kg). In contrast, contraction of the urinary bladder elicited by electrical stimulation of the locus coeruleus was significantly suppressed by intravenous injection of flavoxate, but not affected by that of Hachimijiogan. These results suggest that Hachimijiogan acts on the afferent pathway from the urinary bladder to the locus coeruleus, thereby inhibiting the micturition reflex, while it has no effects on the efferent pathway from the locus coeruleus to the urinary bladder.