Norlin A, Finley N, Abedinpour P, Folkesson H G
Department of Animal Physiology, Lund University, Sweden.
Am J Physiol. 1998 Feb;274(2):L235-43. doi: 10.1152/ajplung.1998.274.2.L235.
Alveolar liquid clearance was examined in ventilated, anesthetized guinea pigs. An isosmolar 5% albumin solution was instilled into the lungs. Alveolar liquid clearance was studied over 1 h and was measured from the increase in alveolar protein concentration as water was reabsorbed. Basal alveolar liquid clearance was 38% of instilled volume. The high basal alveolar liquid clearance was not secondary to endogenous catecholamine release. Compared with control animals, epinephrine and the general beta-adrenergic agonist isoproterenol increased alveolar liquid clearance to approximately 50% of instilled volume (P < 0.05), whereas the beta 2-adrenergic agonist terbutaline was without effect. The stimulation of alveolar liquid clearance by epinephrine or isoproterenol was completely inhibited by the addition of the general beta-adrenergic inhibitor propranolol or the beta 1-adrenergic inhibitor atenolol. Alveolar liquid clearance was inhibited by the sodium-channel inhibitor amiloride by 30-40% in control animals and in animals treated with epinephrine or isoproterenol. Isoproterenol and epinephrine, but not terbutaline, increased adenosine 3',5'-cyclic monophosphate in in vitro incubated lung tissue. The results suggest that alveolar liquid clearance in guinea pigs is mediated partly through amiloride-sensitive sodium channels and that alveolar liquid clearance can be increased by stimulation of primarily beta 1-adrenergic receptors.
在通气的麻醉豚鼠中检测肺泡液体清除率。将等渗的5%白蛋白溶液注入肺中。在1小时内研究肺泡液体清除率，并根据水重吸收时肺泡蛋白浓度的增加来测量。基础肺泡液体清除率为注入量的38%。高基础肺泡液体清除率并非内源性儿茶酚胺释放所致。与对照动物相比，肾上腺素和通用β肾上腺素能激动剂异丙肾上腺素可将肺泡液体清除率提高至注入量的约50%（P<0.05），而β2肾上腺素能激动剂特布他林则无作用。添加通用β肾上腺素能抑制剂普萘洛尔或β1肾上腺素能抑制剂阿替洛尔可完全抑制肾上腺素或异丙肾上腺素对肺泡液体清除率的刺激。在对照动物以及用肾上腺素或异丙肾上腺素处理的动物中，钠通道抑制剂氨氯地平可使肺泡液体清除率降低30%-40%。异丙肾上腺素和肾上腺素可增加体外孵育的肺组织中的3',5'-环磷酸腺苷，但特布他林无此作用。结果表明，豚鼠的肺泡液体清除率部分通过氨氯地平敏感的钠通道介导，并且主要通过刺激β1肾上腺素能受体可增加肺泡液体清除率。
