Liggett S B
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri.
Am Rev Respir Dis. 1989 Feb;139(2):552-5. doi: 10.1164/ajrccm/139.2.552.
Human alveolar macrophages obtained by bronchoalveolar lavage were studied with the high specific activity beta-adrenergic ligand [125I]pindolol and found to possess a moderate density of beta-adrenergic receptors. Using macrophage membranes, the receptor density (Bmax) was 42 +/- 9 fmol/mg protein with an apparent equilibrium dissociation constant (Kd) of 44 +/- 9 pM (mean +/- SEM). With intact macrophages, the Bmax = 5,643 +/- 942 sites/cell with Kd = 29 +/- 9 pM. Competition binding studies with subtype-specific antagonists revealed an exclusive population of beta 2-adrenergic receptors. Incubation of intact macrophages with the beta-adrenergic agonist isoproterenol caused a 6-fold increase in intracellular cyclic AMP (cAMP). Prostaglandin E1 and forskolin, which activate adenylate cyclase via different mechanisms, afforded typical marked increases in macrophage cAMP. Saturation binding, competition binding, and cAMP accumulation studies may all be performed from a single sample of about 2 x 10(7) cells, which can be obtained by bronchoalveolar lavage. This should facilitate studies of in vivo regulation of human alveolar macrophage beta-adrenergic receptors with regard to immune function and mediator release, and as a possible reflection of lung parenchymal receptors.
通过支气管肺泡灌洗获得的人肺泡巨噬细胞，用高比活性的β-肾上腺素能配体[125I]吲哚洛尔进行研究，发现其具有中等密度的β-肾上腺素能受体。使用巨噬细胞膜，受体密度（Bmax）为42±9 fmol/mg蛋白，表观平衡解离常数（Kd）为44±9 pM（平均值±标准误）。对于完整的巨噬细胞，Bmax = 5,643±942个位点/细胞，Kd = 29±9 pM。用亚型特异性拮抗剂进行的竞争结合研究揭示了β2-肾上腺素能受体的单一群体。用β-肾上腺素能激动剂异丙肾上腺素孵育完整的巨噬细胞会导致细胞内环磷酸腺苷（cAMP）增加6倍。前列腺素E1和福斯高林通过不同机制激活腺苷酸环化酶，使巨噬细胞cAMP显著增加。饱和结合、竞争结合和cAMP积累研究都可以从约2×10(7)个细胞的单个样本中进行，该样本可通过支气管肺泡灌洗获得。这应有助于研究人肺泡巨噬细胞β-肾上腺素能受体在免疫功能和介质释放方面的体内调节，以及作为肺实质受体的可能反映。
