锰离子、锌离子、钡离子和钙离子对绵羊十二指肠体外自发运动的影响。

The effect of Mn2+, Zn2+, Ba2+ and Ca2+ on spontaneous motility in sheep duodenum in vitro.

Murillo M D, Plaza M A, Arruebo M P

Departamento de Farmacología y Fisiología (Fisiología), Facultad de Veterinaria, Zaragoza, Spain.

Gen Pharmacol. 1997 Jan;28(1):65-71. doi: 10.1016/s0306-3623(96)00162-0.

Abstract

The effects of several ions, Mn2+, Zn2+, Ba2+ and Ca2+, on spontaneous motility were investigated in longitudinal smooth muscle strips from sheep duodenum, in vitro. 2. Mn2+ (0.5-1.5 mM) and Zn2+ (0.5-5 mM) inhibited both the amplitude and frequency of motility in Krebs solution and in Ca(2+)-free medium. 3. Ba2+ (0.5-5 mM) evoked three types of contractile responses: (i) an increase in the frequency and a reduction of the amplitude of spontaneous contractions; (ii) a slight increase in muscle tone of the phasic contractions; and (iii) a rapid initial phasic contraction followed by slowly fading contraction. Ca2+ induced two kinds of responses in spontaneous motility: (i) a fast phasic contraction, followed by an increase in the amplitude and frequency of phasic contractions with no changes in its tone; and (ii) an increase in the amplitude of contractions. 4. The Ba(2+)-induced contractions were inhibited by EDTA, verapamil and diltiazem, but were not modified by sodium nitroprusside. The Ca(2+)-induced contractions were reduced by verapamil and diltiazem. 5. Our results show that Mn2+ and Zn2+ behave as inhibitors of sheep duodenum motility. In contrast, Ba2+ and Ca2+ stimulate motility. It is suggested that Ba2+ can penetrate the cells through voltage-dependent Ca2+ channels and behave as a partial substitute for Ca2+.

摘要

在体外对来自绵羊十二指肠的纵行平滑肌条中几种离子（锰离子、锌离子、钡离子和钙离子）对自发运动的影响进行了研究。2. 锰离子（0.5 - 1.5毫摩尔）和锌离子（0.5 - 5毫摩尔）在克雷布斯溶液和无钙培养基中均抑制运动的幅度和频率。3. 钡离子（0.5 - 5毫摩尔）引发三种类型的收缩反应：（i）自发收缩频率增加而幅度减小；（ii）相性收缩的肌张力略有增加；（iii）快速的初始相性收缩，随后是逐渐减弱的收缩。钙离子在自发运动中引发两种反应：（i）快速的相性收缩，随后相性收缩的幅度和频率增加，但其张力无变化；（ii）收缩幅度增加。4. 钡离子诱导的收缩被乙二胺四乙酸、维拉帕米和地尔硫䓬抑制，但不受硝普钠影响。钙离子诱导的收缩被维拉帕米和地尔硫䓬减弱。5. 我们的结果表明，锰离子和锌离子表现为绵羊十二指肠运动的抑制剂。相反，钡离子和钙离子刺激运动。提示钡离子可通过电压依赖性钙离子通道进入细胞，并表现为钙离子的部分替代物。