Study on Ca^<2+> sensitivity of reperfusion hypertrophied immature heart

我们在幼兔上建立了一个先天性心脏病的原位模型。本实验采用离体肥厚心肌超负荷灌注，研究了未成熟赫拉特心肌再灌注损伤的机制。首先，我们研究了细胞外钙离子浓度对全脑缺血后功能恢复的影响。结果1）缺血40 min后再灌注时，Ca ^&lt;2+&gt;浓度从1.75 mM增加到2.5 mM，可改善1周龄兔心的机械功能; 2）Na^+/H^+抑制剂（Na^+/H^+抑制剂）可抑制Ca^&lt;2+浓度的升高，并可抑制Ca ^&lt;2+浓度的升高，使Ca ^&lt;2+浓度升高，使（amirolide），据报道可改善成人心脏的机械功能，结果表明：（1）Ca ^&lt;2 +&gt;增敏剂对未成熟再灌注心脏无明显影响;（2）Cl^-/HCO 3 ^-抑制剂（SITS）对1周龄再灌注兔心无明显影响;（3）Ca^&lt;2+&gt;增敏剂对未成熟再灌注兔心无明显影响（匹莫苯）显著改善了再灌注未成熟兔心脏的收缩功能。5）我们改进了灌注系统，使高能磷酸盐信号可以在安装有25 mm线圈的13 P-NMR中每4分钟检测<32>一次。

We developed chlonic pressure overloaded or volume overloaded heart on immature rabbits as a in situ model of congenital heart desease. The isolated hypertrophied heats subjected to overload were perfused and studied the mechanism of reperfusion injury in immature herat. was stuied Firstly, we studied effects of extracellular calcium concentrations on functional recovery after global ischemia. Secondly, the relation between intracardiac pH and Ca^<2+> sensitivity of contractile proteins in reperfused immature hearts.Results1)Increase of Ca^<2+> from 1.75mM to 2.5mM at the initiation of reperfusion after 40 min of global ischemia improved mechanical function of isolated one-week old rabbit hearts.2)Na^+/H^+ inhibiter (amirolide), reported to improve mechanical function of adult heart, showed no remarkable effect on immature reperfused hearts.3)No significant effect has also seen in addition of Cl^-/HCO3^- inhibiter (SITS) on reperfused one-week old rabbit hearts.4)Ca^<2+> sensitizer (pimobendan) improved dramatically contractile function of reperfused immature rabbit herats.5)We modified perfusion system to allow that high energy phosphates signal can be detected at each 4 min in ^<32>P-NMR mounted 25mm coil.