低温对犬血浆肾上腺髓质素和内皮素含量及血流动力学的影响

Effect of hypothermia on the plasma levels of adrenomedullin,endothelin-1 and hemodynamics in dogs

目的：通过低温犬模型，探讨低温对机体血浆肾上腺髓质素（ＡＤＭ）和内皮素（ＥＴ）含量及血流动力学的影响。方法：１２ 条犬随机分为常温〔中心温度控制在（３８．５±０．５）℃〕及低温〔中心温度控制在（３２．０±０．５）℃〕２ 组，在血流动力学监测下测定动物静脉血ＡＤＭ 和ＥＴ。结果：实验犬血浆ＡＤＭ、ＥＴ水平常温组为（２２．３０±１．８０）ｎｇ／Ｌ和（８２．７６±１４．４２）ｎｇ／Ｌ；低温组降温１小时其值分别为（３４．７０±２．１０）ｎｇ／Ｌ和（１６５．２４±１２．５６）ｎｇ／Ｌ，低温犬血浆ＡＤＭ、ＥＴ水平均非常明显增高（Ｐ 均＜ ０．０１），血流动力学指标ＭＡＰ、ＰＡＰ、ＰＣＷＰ和ＣＯ 均发生明显变化（Ｐ均＜ ０．０５）。结论：低温状态下犬血浆ＡＤＭ 及ＥＴ均明显增高，可能在机体血流动力学的调节过程中起重要作用。

Objective:To investigate the influence of hypothermia on plasma levels of adrenomedullin (ADM),endothelin1 (ET1) and hemodynamics in dogs.Methods:The core temperature in normothermic group remained at (38 5±0 5)℃ and that in hypothermic group was cooled to (32 0±0 5)℃ by the body surface cooling with an ice pack.12 dogs were randomly into normothermic and hypothermic groups.Plasma ADM and ET1 levels were measured by radioimmunoassay.Results:The plsama levels of ADM,ET1 in normothermic group were (22 30±1 80)ng/L and (82 76±14 42)ng/L,and that of hypothermic group were (34 70±2 10)ng/L and (165 24±12 56)ng/L.Compared with normothermic group the plasma levels of ADM and ET1 were increased and hemodynamic data were changed significantly in hypothermic dogs ( P <0 05 or P <0 01).Conclusions:The results indicate that the increased plasma level of ADM、ET1 may be one reason of hemodynamic changes in hypothermia.On the basis of our findings the secreted ADM is related to dilate blood vessels as an endotheliumderived relaxing factor competing with ET1.