Effects of inorganic ions on the detrusor contraction induced by electro field stimulation

采用离体大鼠逼尿肌肌条观察镁离子对逼尿肌收缩的影响。肌壁内神经刺激引起的逼尿肌收缩力在无镁溶液中增加，但在高镁溶液中降低。累积加入MgCl（-）2（-）抑制逼尿肌电诱导的收缩反应，呈剂量依赖性。镁离子还以剂量依赖的方式抑制阿托品抵抗的逼尿肌收缩。镁离子抑制氨甲酰胆碱和钾诱导的逼尿肌收缩。镁离子对逼尿肌收缩的作用可被维拉帕米增强，而被Bay-K8644抑制。镁离子对逼尿肌收缩力的抑制作用可被丙酸镁增强。然而，咖啡因并没有改变镁离子的影响。这些结果表明，镁离子抑制逼尿肌收缩，通过抑制作用于平滑肌细胞膜上的钙通道的机制。我们还研究了类似的效应。 ...更多信息 本文观察了电刺激膀胱壁内神经引起的人神经原性膀胱逼尿肌收缩，并与对照膀胱作了比较。神经源性膀胱对膀胱壁内刺激的反应明显强于对照膀胱。河豚毒素几乎完全抑制两组逼尿肌收缩。应用阿托品后，神经源性膀胱的剩余收缩明显大于对照组。阈下KCL对对照组逼尿肌收缩力的增强作用明显强于神经原性膀胱。神经原性膀胱在无钙溶液中的收缩持续时间比对照组长。总之，虽然逼尿肌收缩力没有内在差异，但神经源性膀胱和对照膀胱对电场刺激的收缩反应、阿托品抵抗、钾的增强反应和无钙溶液中的收缩力存在显著差异。少

The effect of magnesium ions on detrusor contraction was investigated in vitro using the rat detrusor muscle strips. Detrusor contractility caused by intramural nerve stimulation increased in a magnesium-free solution but decreased in a high magnesium solution. Cumulative addition of MgCl(-)2(-) suppressed the electrically induced contractile response of the detrusor dose-dependently. Mg-ion also suppressed atropine resistant detrusor contraction in a dose-dependent manner. Mg ion suppressed the detrusor contraction induced by carbachol and potassium. The effect of Mg ion on detrusor contraction was enhanced by verapamil, but was inhibited by Bay-K8644. Procaine increased the inhibitory effect of Mg ion on detrusor contractility. However, caffeine did not modify the effect of Mg ion. These results suggest that Mg ion suppresses detrusor muscle contractility through an inhibitory mechanism acting on calcium channels in the smooth muscle cell membrane. We also investigated similary effec … More ts of Mg ion on rabbit whole bladder.The detrusor contraction induced by intramural nerve stimulation in human neurogenic bladders was investigated in comparison with control bladders. The response of neurogenic bladders induced by intramural stimulation was significantly stronger than that of control bladders. Tetrodotoxin almost completely inhibited the detrusor contraction in both groups. After application of atropine remaining contraction of neurogenic bladders was significantly greater than that of control bladders. The subthreshold KCL ehanced the detrusor contractility significantly more in control bladders compared to neurogenic bladders. The contraction of neurogenic bladders in Ca-free solution persisted longer than that of controls. In conclusion, though there was no intrinsic difference in detrusor contractility, contractile response to electrical field stimulation, atropine resistance, enhancement of response by pottasium, and contractility in Ca-free solution were significantly different between neurogenic and control bladders. Less