松萝酸对兔离体肠平滑肌运动的舒张作用

Effects of usnic acid on smooth muscle of small intestine of rabbit

以兔离体肠平滑肌为研究对象,考察松萝酸对兔离体肠平滑肌运动的影响,并探讨其作用机制。利用BL-420E生物机能实验系统,观察松萝酸对兔离体小肠平滑肌自主收缩的影响;采用工具药乙酰胆碱、组胺、氯化钡诱导小肠平滑肌收缩,并记录小肠平滑肌收缩频率和振幅。采用IP3受体阻断剂肝素、肌浆网ryanodine受体阻断剂钌红(RR)和一氧化氮合酶抑制剂左旋硝基精氨酸甲脂(L-NAME),探明松萝酸对兔离体肠平滑肌作用的机制。结果发现,松萝酸可抑制兔离体小肠平滑肌收缩,具有浓度依赖性,且对乙酰胆碱、组胺、氯化钡诱导的肠肌收缩具有显著的抑制作用。IP3受体阻断剂肝素可增强松萝酸舒张肠平滑肌运动的频率(P<0.01)和振幅(P<0.05),肌浆网ryanodine受体阻断剂钌红和一氧化氮合酶抑制剂左旋硝基精氨酸甲酯可显著增强松萝酸舒张兔离体肠平滑肌运动的频率,对振幅影响不显著。说明松萝酸可显著抑制兔离体小肠平滑肌收缩的频率和振幅,其机制可能与增加一氧化氮浓度,抑制IP3受体和肌浆网ryanodine受体介导的内钙释放有关。

To investigate the effect of usnic acid(UA)on rabbit intestine smooth muscle contraction and the mechanism of the action. METHODS:Used the in vitro intestine movement experiment,with the BL-420 E biologic function analysis system. The influences of UA on the spontaneous contraction of intestine and contraction induced by acetylcholine(ACh),histamine(HA)and Ba Cl2 were observed and the mechanism of UA was studied using inositol 1,4,5-trisphosphate(IP3)receptor antagonist(Heparin,HP),ryanodine receptor antagonist(ruthenium red,RR)and a nitric oxide synthase(NOS)inhibitor(Nitro-L-arginine methyl ester,L-NAME). The results showed that the low concentration of UA excited the spontaneous contraction of intestinal smooth muscle,and the high concentration of UA inhibited that. The high concentration of UA significantly inhibited the muscle contractions induced by ACh,HA and Ba Cl2(P<0.05). HP and RR could strengthen the inhibitory effect of UA on intestinal smooth muscle(P<0.05),L-NAME relieved the inhibitory effect of UA(P<0.01). The results showed the inhibitory mechanism of UA on intestinal smooth muscle contraction may be related to increasing NO concentration in intestinal smooth muscle,and inhibit intracellular Ca2+releasing via IP3 and ryanodine of sarcoplasmic reticulum.