Ros-Moreno R M, Moreno-Guzmán M J, Jiménez-González A, Rodríguez-Caabeiro F
Parasitology and Microbiology Department, Faculty of Pharmacy, University of Alcalá, Alcalá de Henares (Madrid), Spain.
Parasitol Res. 1999 Apr;85(4):320-3. doi: 10.1007/s004360050555.
The value of the gamma-aminobutyric acid (GABA) receptor of nematodes as a target for ivermectin's mode of action remains unclear. Using binding assays, we examined extracts from Trichinella spiralis muscle larvae for the presence of [3H]-ivermectin and [3H]-GABA binding sites. Tissue preparations displayed affinity binding sites for [3H]-ivermectin with a dissociation constant (Kd) of 83 nM and a receptor density (Bmax) of 145 fmol/mg protein. We also identified a specific [3H]-GABA binding activity with a Kd of 1.2 microM and a Bmax of 4.78 pmol/mg protein. In competition studies, ivermectin was found to be a competitive inhibitor of specific [3H]-GABA binding activity with an inhibition constant (K(i)) of 3.39 nM, suggesting that GABA receptors could be implicated in the mechanism of action of ivermectin in nematodes.
线虫的γ-氨基丁酸（GABA）受体作为伊维菌素作用模式的靶点，其价值仍不清楚。我们通过结合试验，检测旋毛虫肌肉幼虫提取物中是否存在[3H]-伊维菌素和[3H]-GABA结合位点。组织制剂显示出对[3H]-伊维菌素有亲和结合位点，解离常数（Kd）为83 nM，受体密度（Bmax）为145 fmol/mg蛋白质。我们还鉴定出一种特异性的[3H]-GABA结合活性，Kd为1.2 μM，Bmax为4.78 pmol/mg蛋白质。在竞争研究中，发现伊维菌素是特异性[3H]-GABA结合活性的竞争性抑制剂，抑制常数（K(i)）为3.39 nM，这表明GABA受体可能参与伊维菌素对线虫的作用机制。
