硫酸锌对在体与离体急性缺氧性肺、脑血管反应的影响

EFFCETS OF ZINC SULFATE ON THE ACUTE HYPOXIC RESPONSES OF PULMONARY AND CEREBRAL BLOOD VESSELS IN VIVO AND IN VITRO

观察了硫酸锌（ＺｎＳＯ＿４）对狗整体肺、脑循环和家兔离休肺内动脉、脑基底劝脉环急性缺氧反应的影响。在整体实验，静脉注射（ｉｖ）硫酸锌１７μｇ·ｋｇ￣(－１)·ｍｉｎ￣(－１)，３０ｍｉｎ后缺氧引起的肺血管阻力的增加值（ΔＰＶＲ）升高；但ｉｖ硫酸锌５０μｇ·ｋｇ￣(－１)·ｍｉｎ￣(－１)后，ΔＰＶＲ降低（Ｐ＜０．０５）。上述剂量硫酸锌对脑血流量及脑血管阻力的缺氧性改变均无显著性影响。在离体血管环实验中，硫酸锌０．１ｍｍｏｌ／Ｌ作用后，内皮完整肺动脉环（ＰＡ￣＋）的缺氧收缩幅度（ＴＩＨ）增加（Ｐ＜０．０５），去内皮肺动脉环（ＰＡ）的ＴＩＨ无显著改变；但在０．３ｍｍｏｌ／Ｌ作用下，ＰＡ￣＋及ＰＡ￣－的ＴＩＨ均降低（Ｐ＜０．０５）。硫酸锌对基底动脉环（ＢＡ￣＋和ＢＡ￣－）缺氧反应无显著影响。结果提示，硫酸锌对血管缺氧反应的影响依剂量大小和血管部位（肺或脑）之不同而异。

Effects of zinc sulfate(ZnSO_4)on the acute hypoxic responses of canine pulmonary and cer-ebral circulation in vivo and of rabbit arterial rings in vilro were observed.In the in vivo experi-ment,the hypoxia-induced increase in pulmonary vascular resistance (ΔPVR)raised after infu-sion of ZnSO_4 17 μg·kg￣(-1)·min￣(-1) for 30 min,while after infusion of ZnSO_4 5μg·kg￣(-1)·min￣(-1),ΔPVR decreased(p<0.05).The hypoxic responses of cerebral circulation had no obvi-ous change under the influences of different dosages of ZnSO_4.In the in vitro experiment onpulmonary and basilar arterial rings,ZnSO_4 0.1 mmol/L caused obvious increase in theamplitude of hypoxia-induced tension(TIH)of endothelium-intact pulmonary arterial rings(PA￣+)while no significant influence on TIH of endothelium-denuded pulmonary arterialrings(PA￣-).ZnSO_4 0.3 mmol/L caused decrease in TIH of both PA￣+ and PA￣-(P<0.05).Thehypoxic responses of basilar rings(BA￣+ and BA)were not affected by ZnSO_4 at both dosages.These results indicate that the effects of ZnSO_4 on the acute hypoxic responses of blood vesselsdepend on its dosage and the location of blood vessels.