Biphasic Modulation of ER-JIN Decalculous Decoction (EJDD) on the Spontaneous Contraction of Porcine Ureteral Smooth Muscle

Background/Purpose. In our previous studies, we showed that ER-JIN Decalculous Decoction (EJDD) could prevent and dissolve experimental bladder calculi. The purpose of this study was further to explore whether EJDD affects the ureteral smooth muscle. Methods. Isolated porcine ureteral smooth muscle was used to investigate the mechamism of EJDD. The smooth muscle was vertically hung in an organ bath comprising 10 mL Kreb's Ringer solution at 37 C with 95% O2 and 5% CO2. Results. Norepinephrine (NE), 5-hydroxytryptamine (5-HT) and PGF(subscript 2a) augmented the frequency and potency of spontaneous smooth muscle contraction in a dose-dependent manner. NE at 1×10^(-4) M and 5-HT at 1×10^(-5) M induced tonic contraction. Spontaneous contraction was inhibited by isoproterenol. EJDD (0.25 to 2 mg/mL) enhanced the frequency and potency of spontaneous contraction in a concentraction-independent manner. EJDD also inhibited the tonic contractions induced by high concentrations of NE and 5-HT. However, the spontaneous contractions induced by NE, 5-HT and PGF(subscript 2a)were inhibited by pretreatment with EJDD. Conclusion. The results suggest that EJDD targets the α, β and 5-HT receptors in islolated procine ureters. The complex effects of EJDD were dependent on endogenous spontaneous contractivity.