Innis R B, Snyder S H
Proc Natl Acad Sci U S A. 1980 Nov;77(11):6917-21. doi: 10.1073/pnas.77.11.6917.
125I-Labeled (Bolton-Hunter) cholecystokinin triacontatriapeptide (CCK-33) binds saturably and reversibly to distinct receptors in brain and pancreatic membranes. The peptide specificity of pancreatic CCK binding is the same as that for pancreatic amylase release. In brain, gastrin and pentagastrin display nanomolar affinity for binding sites, whereas in pancreas these two peptides are virtually inactive. Though these differences indicate that brain and pancreas possess distinct CCK receptors, the two tissues show some similarities. Both pancreas and brain receptors show greater sensitivity to sulfated than to desulfated COOH-terminal octapeptide of CCK and display dissociation constants of 0.3-9.5 nM. The pancreas possesses about 300 times more binding sites than does brain. CCK binding in both brain and pancreas is enhanced by divalent cations and reduced by monovalent cations. Receptor binding in both tissues is regulated in a selective fashion by guanyl nucleotides.
125I标记（博尔顿-亨特法）的胆囊收缩素三十三联肽（CCK-33）可饱和且可逆地结合于脑和胰腺膜中的不同受体。胰腺CCK结合的肽特异性与胰腺淀粉酶释放的肽特异性相同。在脑中，胃泌素和五肽胃泌素对结合位点具有纳摩尔亲和力，而在胰腺中这两种肽几乎无活性。尽管这些差异表明脑和胰腺拥有不同的CCK受体，但这两种组织也存在一些相似之处。胰腺和脑受体对硫酸化的CCK羧基末端八肽的敏感性均高于去硫酸化的八肽，且解离常数为0.3 - 9.5 nM。胰腺拥有的结合位点比脑多约300倍。脑和胰腺中的CCK结合均因二价阳离子而增强，因一价阳离子而减弱。两种组织中的受体结合均受到鸟苷酸的选择性调节。
