三磷酸肌醇对大鼠离体逼尿肌肌条自发收缩作用的影响

目的:观察三磷酸肌醇(IP3)对大鼠逼尿肌肌条自发收缩频率及收缩幅度的作用。方法:建立逼尿肌不稳定(DI)大鼠模型,制作大鼠离体逼尿肌肌条,比较同等张力下DI及逼尿肌稳定(detrusorstability,DS)组逼尿肌肌条自发收缩频率和收缩幅度的变化,观察不同浓度IP3及其抑制剂肝素对二组肌条自发收缩频率和收缩幅度的影响。结果:大鼠膀胱下尿路梗阻6周后DI发生率为57.4%。同等张力下,DI组肌条自发收缩频率显著高于DS组(P<0.01),收缩幅度显著低于DS组(P<0.01)。IP3能显著增加DI、DS大鼠逼尿肌肌条自发收缩频率及收缩幅度(P<0.01),肝素能显著抑制DI鼠逼尿肌肌条的自发收缩频率(P<0.05),但对其收缩幅度没有显著影响(P<0.05)。结论:IP3能显著提高大鼠逼尿肌肌条自发收缩频率和收缩幅度,DI逼尿肌自发兴奋性升高可能与IP/Ca2 信号通路的改变有密切联系。

The influence of IP3 on automatic contractility of isolated detrusor strip in rats

Objective:To investigate the role of IP_3 on the range and frequency of the automatic contractility of isolated detrusor strip in rats.Methods:The rat model of DI was made and detrusor strip was prepared. Changes in the range and frequency of the automatic contractility of isolated detrusor strip in DI and DS rats at fixed tension ( 1.0 g) were determined and compared for evaluating the effect of different concentrations IP_3 on the range and frequency of the spontaneous contractility of detrusor strip.Results:The rate of DI after 6 weeks' obstruction of lower urinary tract was 57.4%.at fixed tension ( 1.0 g),the frequency of contractility in DI group was significantly higher than those of DS group (P< 0.01),but the range of contractility in DI group was lower than those of DS group (P< 0.01). IP_3 could obviously increase the range and frequency of contractility in DI and DS rats (P< 0.01).Heparin could inhibit the frequency of automatic contractility in DI rats (P< 0.05), but no effect on the range of contractility (P< 0.05).Conclusions:IP_3 could increase the range and frequency of the automatic contractility of islated detrusor strip in rats .It might have the intimate relation between the incrensing of detrusor excitability in DI rats and the changes of IP_3/Ca 2 signal pathway.