ヒスタミン肺水腫の研究

Study on histamine induced pulmonary edema

　ヒスタミンは肺血管床に対してvasoconstrictiveに作用するとする説とvasodilativeに作用する説があり実験動物の投与量の差によって一定しない。また透過性昂進作用については肺血管床が作用部位とする説がある一方，気管支循環系の関与が重要とする説がありこれも一定しない。

　我々はヒスタミンを肺動脈内ならびに気管支動脈内へ持続注入することによって肺血行動態と血管の透過性の相違を比較検討した。

　Using sheep with lung lymph flowing through right thoracotomy dose-dependent increase in lung lymph flow and microvascular permeability to protein were observed by injection of histamine into bronchial (0.1—10μg/kg min) or pulmonary artery (1—10 μg/kg min).

　Postmortem extravascular water content was very high. Pattern of vascular permeability to protein expressed in terms of lung lymph protein clearance and permeability surface product was almost the same in both groups of histamine infusion. Infusion of antihistamine caused reversible effect on edema process. Pulmonary vascular resistance was constant or minimal change during infusion of histamine into bronchial artery, while infusion of histamine into pulmonary artery resulted in vasodilative action (decreased pulmonary arterial pressure, constant left atrial pressure and cardiac output) in small dose (1—3μg/kg min) and histamine shock condition with increased pulmonary vascular resistance in large dose (10 μg/kg min).