Sumner M J, Humphrey P P
Pharmacology Division, Glaxo Group Research, Hertfordshire.
Br J Pharmacol. 1989 Sep;98(1):29-31. doi: 10.1111/j.1476-5381.1989.tb16856.x.
We have examined the binding of 5-carboxamidotryptamine (5-CT) and GR43175 (3-(2-dimethylamino)ethyl-N-methyl-1H-indole-5-methane sulphonamide) to 5-HT1D sites labelled with [3H]-5-hydroxytryptamine [( 3H]-5-HT) in neonatal porcine caudate membranes. In competition studies, 5-CT produced shallow inhibition curves (Ki 138 nM, slope 0.31), indicating binding site heterogeneity, while GR43175 interacted with a single population of binding sites (Ki 251 nM, slope 0.98), producing a maximum of only 52% inhibition of [3H]-5-HT binding compared to 100% for 5-HT or 5-CT. In the presence of excess GR43175 (10 microM), 5-CT produced a monophasic inhibition curve with a Ki value of 800 nM for the remaining sites (slope 0.89). These preliminary data suggest that under the conditions employed, GR43175, and to a lesser extent 5-CT, may discriminate between two sub-populations of 5-HT1D binding sites in porcine brain.
我们研究了5-羧基氨基色胺（5-CT）和GR43175（3-(2-二甲基氨基)乙基-N-甲基-1H-吲哚-5-甲磺酰胺）与新生猪尾状核膜中用[3H]-5-羟色胺（[3H]-5-HT）标记的5-HT1D位点的结合情况。在竞争研究中，5-CT产生浅抑制曲线（Ki为138 nM，斜率为0.31），表明结合位点存在异质性，而GR43175与单一群体的结合位点相互作用（Ki为251 nM，斜率为0.98），与5-HT或5-CT对[3H]-5-HT结合的100%抑制相比，其对[3H]-5-HT结合的最大抑制仅为52%。在存在过量GR43175（10 microM）的情况下，5-CT对剩余位点产生单相抑制曲线，Ki值为800 nM（斜率为0.89）。这些初步数据表明，在所采用的条件下，GR43175以及在较小程度上的5-CT可能能够区分猪脑中5-HT1D结合位点的两个亚群。
