目的　探讨低温对兔肺动脉、肾动脉、颈动脉内皮依赖性舒张与非内皮依赖性舒张的影响。方法　选 2 4只白兔 ,每 8只兔取一种血管环 ,每一实验组血管环选自同一只白兔。 8只血管环为一实验组 ,随机分为对照组 (37℃ )、实验组 1(30℃ )、实验组 2 (2 4℃ )、实验组 3(16℃ )。建立不同低温乙酰胆碱、硝酸甘油浓度依赖性曲线。测定不同低温对乙酰胆碱及硝酸甘油引起动脉内皮依赖性舒张及非内皮依赖性舒张的影响。结果　各低温组与常温组及前一低温组之间相比 ,低温抑制肺动脉、肾动脉、颈动脉内皮依赖性舒张与非内皮依赖性舒张 (P <0 .0 0 1)。结论　低温抑制动脉内皮依赖性舒张与非内皮依赖性舒张功能减弱 ,这对心脏手术后并发症的发生机制的深入理解有重要临床意义。 Objective To investigate the effects of hypothermia on endothelium-dependent relaxation and non-endothelium-dependent relaxation of pulmonary arteries, renal arteries and carotid arteries in rabbits. Methods Twenty-four white rabbits were selected, and one of them was taken from every eight rabbits. The vascular rings of each experimental group were selected from the same rabbits. Eight vascular rings were randomly divided into control group (37 ℃), experimental group 1 (30 ℃), experimental group 2 (24 ℃) and experimental group 3 (16 ℃). To establish the different low-temperature acetylcholine, nitroglycerin concentration-dependent curve. The effects of different hypothermia on endothelium-dependent relaxation and non-endothelium-dependent relaxation induced by acetylcholine and nitroglycerin were measured. Results Low temperature inhibited endothelium-dependent relaxation and non-endothelium-dependent relaxation of pulmonary artery, renal artery and carotid artery in all the hypothermia groups compared with the normal temperature group and the former hypothermia group (P <0.01). CONCLUSION: Hypothermia inhibits endothelium-dependent relaxation and non-endothelium-dependent relaxation in aorta, which has important clinical significance for further understanding of the pathogenesis of postoperative complications after cardiac surgery.