Bell D A, Peeters G A, Davis W L, Kohmoto O, Nelson J A, Barry W H
Department of Medicine, University of Utah School of Medicine, Salt Lake City 84132.
Invest Radiol. 1988 Nov;23(11):842-6. doi: 10.1097/00004424-198811000-00008.
To investigate the mechanisms of the negative inotropic effects of contrast media, we superfused spontaneously contracting cultured chick embryo ventricular cells with Renografin-76 and iohexol (12% solutions), and hypertonic sucrose during simultaneous measurement of [Ca2+]i transients (indo-1) and motion (video-motion detector system). Exposure to contrast agents caused a significant reduction of contractility, with Renografin-76 having a much greater effect on amplitude of motion than iohexol. Renografin-76 significantly depressed [Ca2+]i transient amplitude, whereas iohexol had no effect. Addition of Ca2+ to correct for calcium binding by Renografin-76 completely reversed its depression of [Ca2+]i transients but only partially reversed the negative inotropic effects. Hypertonic sucrose caused a significant decrease in contraction amplitude, with no significant effects on [Ca2+]i transient amplitude. We conclude that the marked negative inotropic effect of Renografin-76 is caused by both calcium binding and hypertonicity. The less marked depression of contractility produced by iohexol likely is a result of hypertonicity and not caused by alteration of [Ca2+]i.
为研究造影剂负性肌力作用的机制，我们在用雷奈酸葡胺-76和碘海醇（12%溶液）以及高渗蔗糖对自发收缩的培养鸡胚心室细胞进行灌流的同时，测量[Ca2+]i瞬变（indo-1）和运动（视频运动检测系统）。暴露于造影剂会导致收缩性显著降低，雷奈酸葡胺-76对运动幅度的影响比碘海醇大得多。雷奈酸葡胺-76显著降低[Ca2+]i瞬变幅度，而碘海醇则无影响。添加Ca2+以校正雷奈酸葡胺-76的钙结合作用可完全逆转其对[Ca2+]i瞬变的抑制，但仅部分逆转负性肌力作用。高渗蔗糖导致收缩幅度显著降低，对[Ca2+]i瞬变幅度无显著影响。我们得出结论，雷奈酸葡胺-76明显的负性肌力作用是由钙结合和高渗性共同引起的。碘海醇引起的收缩性降低不太明显，可能是高渗性的结果，而非由[Ca2+]i改变所致。
