阿托品对兔胸主动脉平滑肌收缩和细胞增殖的影响

EFFECTS OF ATROPINE ON CONTRACTION OF RABBIT AORTIC SMOOTH MUSCLE AND CELL PROLIFERATION

用兔胸主动脉条研究Atr,Ver对CaCl_2,Atr对KCI量—效反应的影响。观察到Atr和Ver能抑制2种激动剂所致兔主动脉条的收缩,量一效曲线右移,最大反应降低,其pD_2值分别为4.4和5.8。两药也能明显抑制NE依内Ca^(2+)性收缩,Atr对NE依外Ca^(2+)性收缩影响较小,说明Atr主要对细胞外Ca^(2+)经PDC所致的收缩有抑制作用。在兔ASMC培养中,有Ca^(2+)时,Atr抑制ASMC增殖,无Ca^(2+)时,Atr 20.6～185.2 μmol/L表现刺激增殖,555.7～1666.7 μmol/L则抑制MSMC增殖,说明Atr对ASMC作用也与Ca(2+)有关。

The calcium antagonistic actions of atropine (Atr) and verapamil (Ver) were studied on the contraction of rabbit thoracic aorta strips induced by CaCl_2 and KCl. Both Atr and Ver were found to depress the contraction as demonstrated by the shift-to-right of the dose--effect relationship curves and the decrease of maximal responses, with the value of pD_2 being 4. 4 and 5.8 respectively. The intracellular Ca^(2+)-dependent component of NE-induced aortic strip contraction was also inhibited by the 2 drugs, but the extracellular Ca^(2+)-dependent component was barely or not inhibited by Atr before its concentration was raised to 100 μmol/L. These results indicate that the depressive effect of Atr on aortic contraction is mainly exerted by acting on the PDC (potential-dependent channel). The action of Atr on proliferation of cells was also studied in rabbit aortic smooth muscle cell (ASMC) culture. The growth was inhibited by Atr when Ca^(2+) was present in the medium. When Ca^(2+) was absent, however, the growth was stimulated by Atr 20. 6～185.2 μmol/L, but inhibited by Ah 555.7～1666.7 μmol/L, suggesting that Ca^(2+) is somehow involved in the action of Atr on ASMC growth.