Agrawal K P, Hyatt R E
J Appl Physiol (1985). 1986 Jun;60(6):2089-93. doi: 10.1152/jappl.1986.60.6.2089.
Tracheal Na+-K+-ATPase activity is positively correlated with in vivo airway responsiveness to histamine. We wondered whether this were a chance association or whether it was directly related to the mechanism of hyperreactivity. Therefore, we obtained dose-response curves to aerosols of histamine and ouabain in guinea pigs to determine whether an in vivo relationship existed between the excitatory effects of histamine and the enzyme-inhibiting effect of ouabain. Airway responsiveness to ouabain was measured as the ouabain concentration producing a 30% decrease in specific airway conductance (ED30) or that producing a half-maximal response (ED50). Responsiveness to histamine was measured either as ED30 or as ED50. Significant positive correlations were noted between the log ED50 of ouabain and log histamine ED30 or ED50 (r = 0.81 and 0.83, respectively; P less than 0.001), and between log ouabain ED30 and log histamine ED30 and ED50 (r = 0.76 and 0.77, respectively; P less than 0.002). Pretreatment with ouabain increased airway responsiveness to histamine (P less than 0.05). We suggest that in hyperreactive airways Na+-K+-ATPase serves a homeostatic function of preventing Na+ and Ca2+ loading of the cell and that it is not directly responsible for the hyperreactivity.
气管钠钾ATP酶活性与体内气道对组胺的反应性呈正相关。我们想知道这是偶然的关联还是与高反应性机制直接相关。因此，我们获得了豚鼠对组胺和气溶乌本苷气雾剂的剂量反应曲线，以确定组胺的兴奋作用与乌本苷的酶抑制作用之间是否存在体内关系。气道对乌本苷的反应性通过产生特定气道传导率降低30%的乌本苷浓度（ED30）或产生最大反应一半的浓度（ED50）来衡量。对组胺的反应性通过ED30或ED50来衡量。乌本苷的对数ED50与组胺对数ED30或ED50之间存在显著正相关（分别为r = 0.81和0.83；P < 0.001），乌本苷对数ED30与组胺对数ED30和ED50之间也存在显著正相关（分别为r = 0.76和0.77；P < 0.002）。用乌本苷预处理可增加气道对组胺的反应性（P < 0.05）。我们认为，在高反应性气道中，钠钾ATP酶起到防止细胞内钠和钙负荷的稳态功能，并且它并非高反应性的直接原因。
