胡椒碱对槟榔碱促进家兔离体小肠平滑肌运动的影响

Effect of piperine on arecoline induced contraction of isolated small intestinal smooth muscle from rabbits

目的观察胡椒碱对槟榔碱促进家兔离体小肠平滑肌运动的影响及其作用机制.方法采用离体平滑肌恒温灌流的方法,取家兔离体小肠,通过BL-420生物机能实验系统测定其张力的变化,观察不同浓度(0.06 g/L、0.6 g/L、6 g/L)胡椒碱溶液对正常状态下家兔离体小肠平滑肌自发性收缩的影响;先观察胡椒碱对家兔离体小肠平滑肌自发性收缩的影响,随后观察加入槟榔碱后对家兔离体小肠平滑肌自发性收缩的影响;为研究胡椒碱抑制家兔离体小肠平滑肌收缩的作用机制,应用IP3受体(inositol 1, 4, 5-trisphosphate, IP3)阻断剂肝素(Heparin,HP)、肌浆网ryanodine受体阻断剂钌红(ruthenium red,RR)和一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(N'-nitro-L-arginine-methylesterhydrochloride,L-NAME),共同阐明胡椒碱对家兔离体小肠平滑肌作用的机制.结果胡椒碱抑制家兔离体小肠平滑肌自发性收缩,药物浓度在6 g/L时可显著抑制家兔离体小肠平滑肌收缩的振幅(P<0.01);在此基础上加入0.006 g/L槟榔碱溶液促进家兔离体小肠平滑肌收缩的振幅(P<0.05)且升高小肠收缩幅度小于单个槟榔碱促进家兔离体小肠平滑肌的收缩振幅(P<0.05); IP3受体HP能增强胡椒碱舒张家兔离体小肠平滑肌收缩的作用(P<0.05),而肌浆网ryanodine受体阻断剂钌红对胡椒碱舒张家兔小肠平滑肌的作用无明显影响(P>0.05); L-NAME能够部分阻断胡椒碱舒张家兔离体小肠平滑肌收缩的作用(P<0.05).结论胡椒碱可显著抑制家兔离体小肠平滑肌收缩的振幅;抑制单个槟榔碱促进家兔离体小肠平滑肌的收缩振幅;其机制可能与增加一氧化氮浓度,抑制IP3受体介导的内钙释放有关,但对肌浆网ryanodine受体途径引起的内钙释放无关.

AIM To investigate the effect of piperine on arecoline induced contraction of isolated small intestinal smooth muscle from rabbits and explore the possible mechanism involved.METHODS The method of ex vitro smooth muscle perfusion at a constant temperature was used to collect the rabbit small intestine in vitro.The effect of piperine solution at concentrations of 0.06 g/L,0.6 g/L,and 6 g/L on the spontaneous contraction of isolated rabbit small intestinal smooth muscle was observed using the BL-420 biofunctional experiment system.Then,the effect of piperine and arecoline,alone or in combination,on spontaneous contraction of isolated small intestinal smooth muscle from rabbits was observed.To explore the mechanism by which piperine affected the contraction of isolated rabbit small intestinal smooth muscle,an inositol 1,4,5-trisphosphate(IP3)receptor antagonist(heparin,HP),a ryanodine receptor antagonist(ruthenium red,RR),and a nitric oxide synthase(NOS)inhibitor(nitro-Larginine methyl ester,L-NAME)were used.RESULTS Piperine inhibited the spontaneous contraction of isolated small intestinal smooth muscle from rabbits.At a concentration of 6 g/L,piperine showed a significant inhibitory effect on the amplitude of spontaneous contractions(P<0.01).On this basis,arecoline solution at 0.006 g/L significantly increased the amplitude of contraction of isolated rabbit small intestinal smooth muscle(P<0.05),but the amplitude of small intestinal smooth muscle contraction was smaller than that treated with arecoline alone(P<0.05).IP3 receptor antagonist heparin could strengthen the relaxation effect of piperine on intestinal smooth muscle(P<0.05),but ryanodine receptor antagonist ruthenium red had no effect on the relaxation effect of piperine(P>0.05).L-NAME inhibited the relaxation effect of piperine(P<0.05).CONCLUSION Piperine can inhibit the amplitude of spontaneous and arecoline induced contraction of rabbit intestinal smooth muscle.The mechanism may be related to the increase of NO concentration in intestinal smooth muscle and the inhibition of intracellular Ca2+release via IP3 of sarcoplasmic reticulum.