Durieux C, Coppey M, Zajac J M, Roques B P
Biochem Biophys Res Commun. 1986 Jun 30;137(3):1167-73. doi: 10.1016/0006-291x(86)90348-7.
Saturation experiments of the highly potent cholecystokinin analogue [3H]Boc(diNle28,31)CCK27-33 ([3H]BNDL-CCK7, 100 Ci/mmol) with guinea pig brain cortex in a large concentration range (0.05 nM to 30 nM) show the presence of two different binding sites (A site: KD = 0.13 nM, Bmax = 35 fmol/mg; B site: KD = 6.4 nM, Bmax = 92 fmol/mg). Both sites exhibit different sensitivity to sodium ions and therefore can be selectively investigated at [3H]BDNL-CCK7 concentration lower than 1 nM for the A site in Tris buffer and in Krebs buffer for the B site. The selectivity factors KIB/KIA of various CCK related peptides vary from 58 for CCK4 to 26 for CCK8 and 4 for the antagonist (Nle28,31) CCK27-32-NH2. The occurrence of two different CCK binding sites in the brain could explain biphasic pharmacological effects of CCK8.
高效胆囊收缩素类似物[3H]Boc(diNle28,31)CCK27 - 33（[3H]BNDL - CCK7，100 Ci/mmol）在较大浓度范围（0.05 nM至30 nM）与豚鼠脑皮质进行的饱和实验表明存在两种不同的结合位点（A位点：KD = 0.13 nM，Bmax = 35 fmol/mg；B位点：KD = 6.4 nM，Bmax = 92 fmol/mg）。两个位点对钠离子表现出不同的敏感性，因此在Tris缓冲液中低于1 nM的[3H]BDNL - CCK7浓度下可选择性研究A位点，在Krebs缓冲液中可选择性研究B位点。各种CCK相关肽的选择性因子KIB/KIA从CCK4的58到CCK8的26以及拮抗剂（Nle28,31）CCK27 - 32 - NH2的4不等。脑中两种不同CCK结合位点的存在可以解释CCK8的双相药理作用。
