Cai Shuang, Mukherjee Jhindan, Tillekeratne L M Viranga, Hudson Richard A, Kirchhoff Jon R
Department of Chemistry, College of Arts and Sciences, The University of Toledo, Toledo, OH 43606, USA.
Bioorg Med Chem. 2007 Nov 15;15(22):7042-7. doi: 10.1016/j.bmc.2007.07.041. Epub 2007 Aug 22.
Both N,N'-(2,3-dihydroxybenzyl)-N,N,N',N'-tetramethyl-1,6-hexanediamine dibromide (DTH, 6) and N,N'-(2,3-dihydroxybenzyl)-N,N,N',N'-tetramethyl-1,10-decanediamine dibromide (DTD, 7), which are symmetrical bis-catechol substituted hexamethonium and decamethonium analogues, respectively, were found to inhibit high-affinity choline transport in mouse brain synaptosomes. Inhibitory properties were evaluated using an extraordinarily sensitive capillary electrophoresis method employing electrochemical detection at an enzyme-modified microelectrode. Dose-response curves were generated for each inhibitor and IC(50) values were determined to be 76 microM for 6 and 21 microM for 7. Lineweaver-Burk analysis revealed that both molecules inhibit high-affinity choline uptake by a mixed inhibition mechanism. The K(I) values for 6 and 7 were determined to be 73+/-1 and 31+/-2 microM, respectively. The inhibition properties were further compared to a series of mono-catechol analogues, 3-[(trimethylammonio)methyl]catechol (1), N,N-dimethylepinephrine (4) and 6-hydroxy-N,N-dimethylepinephrine (5), as well as the well-characterized hemicholinium inhibitors, hemicholinium-15 (HC-15, 8) and hemicholinum-3 (HC-3, 9).
N,N'-（2,3-二羟基苄基）-N,N,N',N'-四甲基-1,6-己二胺二溴化物（DTH，6）和N,N'-（2,3-二羟基苄基）-N,N,N',N'-四甲基-1,10-癸二胺二溴化物（DTD，7），分别是对称的双儿茶酚取代的六甲铵和十甲铵类似物，被发现可抑制小鼠脑突触体中的高亲和力胆碱转运。使用在酶修饰微电极上进行电化学检测的极其灵敏的毛细管电泳方法评估抑制特性。为每种抑制剂生成剂量-反应曲线，确定6的IC(50)值为76 microM，7的IC(50)值为21 microM。Lineweaver-Burk分析表明，这两种分子均通过混合抑制机制抑制高亲和力胆碱摄取。确定6和7的K(I)值分别为73±1 microM和31±2 microM。将抑制特性进一步与一系列单儿茶酚类似物、3-[(三甲基铵基)甲基]儿茶酚（1）、N,N-二甲基肾上腺素（4）和6-羟基-N,N-二甲基肾上腺素（5），以及特征明确的半胆碱抑制剂半胆碱-15（HC-15，8）和半胆碱-3（HC-3，9）进行比较。
