黄体酮对离体大鼠胸主动脉条收缩反应的影响

THE RELAXING EFFECT OF PROGESTERONE ON SEPARATED THORACIC AORTA STRIPS OF RATS

黄体酮(Pro)可使KCI(60 mmol/L)或NE(1μmol/L)诱发的肌条收缩明显松驰,IC_(50)分别为70.3和93.9(μmol/L);而戊脉安(Ver)的IC_(50)则分别为0.085和0.766(μmol/L)。Pro和Ver均可使NE或CaCl_2引起的肌条收缩量效曲线右移,最大效应降低。呈非竞争性拮抗:Pro的PD_2′分别为4.072和4.688,Ver的PD_2′为5.563和6.456。无钙液中加入NE 1μmol/L引起肌条收缩(1相),再加入CaCl_22.5mmol/L引起再次收缩(2相):Pro可显著抑制上述两种收缩,而Ver仅对2相收缩有显著抑制作用。以上结果表明:黄体酮有直接扩张血管作用,它与钙拮抗剂戊脉安相似,对电压依赖性钙通道及受体调控性钙通道均有阻滞作用;此外,它还能抑制NE激活的细胞内钙的释放。

On separated thoracic aorta strips of S.D. rats Progesterone(Pro) and Verapamil(Ver) were able to relax significantly the constricted tissue stimulated by potassium chlorid (KCl 60mmol/L) or noradrenaline (NE 1 μmol/L). The IC_(50) value of Pro was (μmol/L) 70.3 and 93.9 respectively, and that of Ver was 0.085 and 0.766. Pro and Ver were also able to make NE or CaCl_2 cumulative log-dose response curves from rat aorta strips shift to the right, and to reduce the maximum response. The PD_2′ value of Pro was 4.072 and 4.688 respectively, and that of Ver was 5.563 and 6.456. Added NE into a Calcium free K-H solution to induce tissue constriction (phase 1), then added calcium to induce continued constriction (phase 2). Pro was able to reduce both of them significantly, but Ver was only able to reduce phase 2. These results suggested that Progesterone had a direct vasodilative effect, which was related to blockade of Calcium channel, both of the potential dependent channel (PDC) and the receptor operared channel (ROC), like calcium channel blocker Verapamil did; besides, it was related to inhibit the calcium release from intracellular storage sites.