RU486对兔输卵管平滑肌的收缩效应

THE EFFECT OF RU486 ON CONTRACTILITY OF RABBIT OVIDUCT SMOOTH MUSCLE

应用肌肉机械－电换能器和Ｇｉｌｓｏｎ生理记录仪，观察ＲＵ４８６对假孕４ｄ兔离体输卵管平滑肌的收缩效应。结果显示：（１）ＲＵ４８６可直接作用输卵管平滑肌，使其收缩频率增加，而未明显改变收缩张力及振幅，与在体肌内注射ＲＵ４８６观察到的结果相似；（２）ＲＵ４８６部分抑制ｃａ^（２＋）诱发的平滑肌收缩活动，它还与Ｖｅｒａｐａｍｉｌ诱发的抑制效应有协同作用，与ＮＥ诱发的收缩张力有拮抗作用，而对Ｆｏｒｓｋｏｌｉｎ诱发的效应未产生任何影响。以上结果表明，ＲＵ４８６对输卵管平滑肌的作用似乎是改变细胞内游离Ｃａ（２＋）的结果，可能干扰Ｃａ（２＋）的流入、或／和内质网Ｃａ（２＋）释放以及Ｃａ（２＋）－Ｉｐ３信息传递机制。

An investigation on the effect of RU486 on isolated ovicluct smooth muscle contraction of pseudopregant rabbits was carried out by using the mechanical-electrical transducer of Galson recorder. The results showed that: (1 ) RU486 acted directly on the oviduct smooth muscle by increasing contractile frequency, without changing tensionand amplitude. This effect is similar to that found in the in ho experiment. (2) RU486 partially inhibited Ca(2+)-induced smooth muscle contraction and also showed significantgynergistic effect of Verapamil and antagonistic effect of NE on muscle contractility. However, RU486 is unable to exert any effect on Forskolin-stimulated contraction.Thus it appears that the RU486 effect on oviduct smooth muscle contraction is a result of affecting intracellular free calium, due possibly to interference of Ca(2+) influx and/or endoplasmic reticulum Ca(2+)release and Ca(2+)-Ip3 transducing mechanism. Present address: (Department of Physiology, Jiangxi Medical College, Nanchang 330006)