The Role of c-AMP and Ca ion on Awake Sheep Lung Injury

(1)绵羊肺损伤是由低压缺氧引起的缺氧性肺血管收缩所致。这一作用可被给予二丁酰c-AMP抑制。无论是减压前20分钟给药，还是暴露后20分钟给药，都证明了这种作用。对于全身血压，db-c-AMP没有引起任何明显的变化。Db、c-AMP对内毒素诱导的肺损伤也有显著的抑制作用。在另一系列实验中，我们的小组成员测试了氯苯那敏(HI受体拮抗剂)、db、c-AMP以及钙通道拮抗剂维拉帕米和硝苯地平对聚溴醚所致肺损伤的预抑制作用。由此发现，只有维拉帕米和db c-AMP能显著减弱聚丙交酯的通透性效应，从而解释了聚乙二烯引起的通透性改变可能受细胞内钙和/或c-AMP水平的调节。(2)细胞通透性…的影响观察了更多的c-AMP二丁酰衍生物对大鼠肺血管反应性的影响。在同种异体血肺灌流中，db c-AMP(30微g/min)可抑制低氧引起的血管收缩和血管紧张素II团注引起的血管收缩。氨茶碱对cAMP磷酸二酯酶的抑制作用与db c-AMP在减轻缺氧引起的血管收缩中具有协同作用。在灌流细胞和无蛋白盐溶液的肺中，db cAMP抑制了团注2微克白三烯C4后的初始和延长的血管收缩。因此认为dbc-AMP非特异性地抑制肺血管反应性。(3)利用兔耳垂浸泡在冷液中，通过开放动静脉吻合来代偿毛细血管血流量。从激光多普勒组织血流仪获得的记录的图案变化中可以注意到这种现象。(4)这些动物实验在某些情况下是在人类高原反应中进行测试的，治疗正在进行测试。较少

(1) Sheep lung injury was produced by hypobaric hypoxia which caused hypoxic pulmonary vasoconstriction. This was inhibited by administration of dibutyryl c-AMP. The effect was proved either in the case of the administration 20min before hypobaric exposure or 20 min after the exposure. For the systemic blood pressure, db c-AMP did not cause any significant change. The inhibitory effect of db c-AMP for endotoxin-induced lung injury was also known tobe remarkable. In another series of experiments our group members tested the pretreatment-inhibition potential of chlorpheniramine ( an HI receptor antagonist), db c-AMP, and the Ca channel antagonists verapamil and nifedipine on polybrene-induced lung injury. It was thus found that only verapamil and db c-AMP significantly attenuated the permeability effects of polybrene.It was interpreted that the permeability alteration induced by polybrene could be modulated by intracellular calcium and/or c- AMP levels.(2) The effects of the cell-permeab … More le dibutyryl derivative of c- AMP on the vascular reactivity of isolated perfused rat lungs were examined. In lungs perfused with homologous blood, pulmonary arterial infusion of db c-AMP (30 micro g/min) inhibited hypoxia- induced vasoconstriction and vasoconstriction due to bolus injection of angiotensin II. Cyclic AMP phosphodiesterase inhibition by aminophylline acted synergistically with db c-AMP in the reduction of hypoxia-induced vasoconstriction. In lungs perfused with cell and protein-free salt solution, db cAMP inhibited both initial and prolonged vasoconstriction following bolus injection of 2 micro g leukotriene C4. It is therefor considered that db c-AMP inhibited pulmonary vascular reactivity nonspecifically.(3) Using rabbit earlobes immersed in cold liquid, capillary blood flow was compensated by opening of arterio-venous anastomoses. This phenomenon was noticed from the pattern change of the record obtained by a laser-Doppler tissue flow meter.(4) These animal experiments were in some cases being tested in human high altitude responses and the treatment is being tested. Less