The Role of Intracellular Ca^<2+> ion and Calmodulin in Organ Preservation

用门颈静脉分流术分离肝脏后观察大鼠存活率。钙调素拮抗剂和钙调素拮抗剂均能显著提高正常肝大鼠和肝硬化大鼠的存活率。研究还发现，在正常肝大鼠和肝硬化大鼠缺血后，钙调素拮抗剂和钙++拮抗剂均能加速ATP的还原，且肝循环恢复后大鼠的存活率与ATP还原率成正比。这些结果被FIPLC和31P-NMR证实。据推测，细胞的存活取决于维持细胞膜上的电位差。我们认为能够有效利用ATP并维持电位差的细胞能够抵抗缺血。也可以认为Ca++拮抗剂和钙调素拮抗剂阻断磷脂酶A2的激活，控制细胞内FFA的增加，从而抑制缺血引起的肝细胞损伤。这是因为细胞内FFA阻断了NaK ATP酶，抑制了ATP的利用。用31P-NMR测定乳酸和其他参数证明了这一点。但通过给药大鼠5FBAPTA，用核磁共振法无法准确测定Ca++离子浓度。一个原因是磁场弱，另一个原因是5FBAPTA的溶剂毒性很大，我们无法给药。我们不能测量细胞内的钙离子，因为荧光光度计最多只能测量10-6 mol。

Rat survival rate was examined after isolation of the liver with porto-jugular vein shunt. Survival rate was significantly increased both in normal liver rats and in liver cirrhosis rats after administering Ca++ antagonist and calmodulin antagonist. It was also found that reduction of ATP was accelerated after ischemia both in normal liver rats and in liver cirrhosis rats by administered calmodulin antagonist and Ca++ antagonist and that rat survival rate after reopening liver circulation was high in proportion to reduction rate of of ATP. These results were confirmed by both FIPLC and 31P-NMR method.It is supposed that survival of the cell depends on the maintenance of potential difference across the cell membrane. We assumed that the cell which can effectively utilize ATP and maintain potential difference can resist ischemia. It was also assumed that Ca++ antagonist and calmodulin antagonist interrupt activation of phospholipase A2 and control the increase of intracellular FFA and then restrain hepatocellular damage caused by ischemia. This is because that intracellular FFA interrupt NaK ATPase and restrain the utilization of ATP. This was proved by measuring lactic acid and other parameters using 31P-NMR. But we could not measure the concentration of Ca++ ion accurately with NMR by administering rats 5FBAPTA. One of the reasons is that the magnetic field is weak and the other is that we cannot administer much dose because dissolvant of 5FBAPTA is much toxic. We could not measure intracellular Ca++ because fluorophotometer can measure 10-6 mol at most.