Carstairs J R, Barnes P J
J Pharmacol Exp Ther. 1986 Oct;239(1):249-55.
Binding of [125I]vasoactive intestinal peptide (VIP) to human and guinea pig lung sections was characterized and VIP receptors localized by light-microscopic autoradiography. Inhibition of [125I] VIP binding by unlabeled VIP, peptide histidine isoleucine, peptide histidine methionine, secretin and VIP fragment VIP10-28 indicated that [125I]VIP bound to specific receptors and binding was shown to be reversible. Scatchard analysis showed two binding sites; human lung and a dissociation constant (Kd) of 0.27 +/- 0.04 and 23.3 +/- 3.5 nM, with maximum binding capacities (Bmax) of 11.2 +/- 3.1 and 589 +/- 98 fmol mg-1 of protein for the high and low affinity sites, respectively. Guinea pig lung similarly had a high affinity Kd of 0.3 +/- 0.05 nM and Bmax of 226 +/- 61.1 fmol mg-1 of protein and a low affinity Kd value of 18.8 +/- 2.4 nM and Bmax of 1730 +/- 260 fmol mg-1 of protein. In both human and guinea pig lung there was labeling of cellular structures and no specific labeling pattern was found in sections incubated in the presence of an excess of unlabeled VIP. A high density of labeling was found over airway epithelium of all airways, submucosal glands and vascular smooth muscle. There was also labeling of airway smooth muscle of large, but not of small, airways. This localization corresponds to the pattern of VIPergic innervation. In addition, there was labeling of alveolar walls. This indicates that VIP has a physiological role in the lung.
通过光学显微镜放射自显影法对[125I]血管活性肠肽（VIP）与人及豚鼠肺组织切片的结合特性进行了表征，并对VIP受体进行了定位。未标记的VIP、肽组氨酸异亮氨酸、肽组氨酸甲硫氨酸、促胰液素和VIP片段VIP10 - 28对[125I]VIP结合的抑制作用表明，[125I]VIP与特异性受体结合，且结合是可逆的。Scatchard分析显示有两个结合位点；人肺组织中，高亲和力位点的解离常数（Kd）为0.27±0.04 nM，最大结合容量（Bmax）为11.2±3.1 fmol mg-1蛋白质；低亲和力位点的Kd为23.3±3.5 nM，Bmax为589±98 fmol mg-1蛋白质。豚鼠肺组织同样具有高亲和力Kd为0.3±0.05 nM，Bmax为226±61.1 fmol mg-1蛋白质，低亲和力Kd值为18.8±2.4 nM，Bmax为1730±260 fmol mg-1蛋白质。在人及豚鼠肺组织中，细胞结构均有标记，在过量未标记VIP存在下孵育的切片中未发现特异性标记模式。在所有气道的气道上皮、黏膜下腺和血管平滑肌上发现了高密度的标记。大气道的气道平滑肌也有标记，但小气道没有。这种定位与VIP能神经支配模式相对应。此外，肺泡壁也有标记。这表明VIP在肺中具有生理作用。
