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Effects of Mg-load on the contraction of uterus in sponteneously diabetic mice

镁负荷对自发性糖尿病小鼠子宫收缩的影响

基本信息

批准号：
08680050
负责人：
AOMINE Masahiro
金额：
$ 1.6万
依托单位：
Nakamura Gakuen University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680050/
关键词：
Mg-load Diabetes mellitus Mouse Uterus Contraction Oxytocin

项目摘要

First, we investigated effects of external magnesium (Mg) on the contractile tension of uterus under the condition of Mg-unload, using spontaneously diabetic mice (KK/tA9 and the non-diabetic mice (c57/BL). Both KK/Ta and C57/BL mice were divided into the folloowing three groups : a group fed with normal diet (N-group) ; a group fed with normal diet, accompanied by pohysical exercice (whirl cage running)(T-group) ; a group fed with restricted diet (a half of normal volume), accompanied by the physical exercice (TD-group). External Mg decreased the amplitude and frequency of the contractile tension of uttlerus in a concentration dependent manner. IC_<50> of Mg in the amplitude and frequency of the tension in both mice was the smallest in N-group, followed by T-group and TD-group in the order. This tendency was more eminent in diabetic mice. Secondly, the inhibitive effects of external Mg on the contractile tension of utterus were studied, using Mg-load mice, and compared with Mg-unload mice. Mg-load was done by 1. p. injection of 2M MgCl_2 for 2 to 3 weeks. In Mg-load KK/Ta mice, serum Mg concentration was significantly higher than in Mg-load C57/Bl, whereas uterus Mg concentration was almost same in both mice. In Mg-unload mice, C57/BL uterus was more sensitive to external Mg than KK/Ta uterus. In Mg-load mice, however, the difference between KK/Ta and C57/BL disappeared, suggesting the relation between the contractility and the Mg concentration in the tissue. In oxytocin-induced contracture, Mg-load suppressed the amplitude of the contracture and significantly shortened the time to the peak contracture. These resyults strogly suggested that Mg may affect the affinity between oxytocin and the receptors, and the density of the receptors.

首先，我们采用自发性糖尿病小鼠（KK/tA 9）和非糖尿病小鼠（c57/BL），研究了在去镁条件下，外源性镁（Mg）对子宫收缩张力的影响。将KK/Ta和C57/BL小鼠分为正常饮食组（N组）、正常饮食+运动组（T组）和限制饮食+运动组（TD组）。外源性镁以浓度依赖性方式降低Uttlerus收缩张力的幅度和频率。镁<50>对两种小鼠张力振幅和频率的IC_（n）均为N组最小，依次为T组和TD组。这种倾向在糖尿病小鼠中更为突出。第二，采用镁负荷小鼠，观察了外源性镁对离体小鼠后肢肌张力的抑制作用，并与去镁小鼠作了比较。Mg负载通过1.腹腔注射2 M MgCl_2，持续2 ~ 3周。在镁负荷的KK/Ta小鼠中，血清镁浓度显著高于镁负荷的C57/B1，而子宫镁浓度在两种小鼠中几乎相同。在去镁负荷小鼠中，C57/BL子宫对外源性镁的敏感性高于KK/Ta子宫。而在镁负荷组，KK/Ta和C57/BL之间的差异消失，提示心肌收缩力与组织中镁浓度有关。在催产素诱导的挛缩中，镁负荷抑制挛缩的幅度，并显著缩短达到峰值挛缩的时间。这些结果提示镁可能影响催产素与受体的亲和力及受体密度。