钙、钾、钠对缺氧性肺血管收缩反应影响的实验研究

用大鼠和离体兔肺动脉环实验模型观察钙（Ca(2＋)）、钾（K＋）、钠（Na＋）对缺氧性肺血管收缩（HPV）的影响。整体实验发现:随血Ca(2 )、Na 浓度增高，HPV显著增强。血K 浓度升高0.36mmol／L，HPV明显减弱;血K 浓度继续升高，HPV又明显增强。离体实验发现:营养液中Ca(2 )浓度由0mmol／L逐步升高至10.0mmol／L的过程中，HPV明显增强。Na 浓度由35mmol／L升至220mmol／L过程中，HPV明显减弱。K 浓度由0mmol／L升高至6mmol／L，HPV明显减弱;继续升高至20mmol／L，HPV又明显增强。机理可能为细胞外钙浓度升高，缺氧时进入细胞内Ca(2 )增多，使HPV增强;K 、Na 主要通过影响细胞膜电位和离子交换起作用。

The Effects of Ca~(2 ), K~ , Na~ on Hypoxic Pulmonary Vasoconstriction

The effects of extracellular Ca(2 ), K and Na concentration on hypoxic pulmonary vasoconstriction (HPV) were studied in both intact rats and isolated pulmonary arterial rings of rabbits. ln vitro, increasing of serum Ca2 concentration and Na concentration significantly potentiated HPV. The effect of K concentration on HPV was biphasic: the slight increasing by 0. 36 mmol/L inhibited HPV, while the considerable increasing potentiated HPV. In vivo, as Ca2 concentration rose from 0 to 10.0 mmol/L, HPV was significantly potentiated, while Na concentration from 35 to 220 mmol/L, HPV was inhibited. The biphase of K ] effects was also observed: when K concentration was 6 mmol/L, HPV was inhibited mostly, while up to 20 mmol/L, HPV was potentiated. The probable mechanisms involved were discussed. When the extracellular Ca2 concentration increased, the influx of Ca2 was enhanced during hypoxia and consequently HPV was potentiated. The effects of Na and K were conducted through affecting membrane potential and ionic exchange.