作者:Stina Saitton、Andria L. Del Tredici、Maria Saxin、Tobias Stenström、Jan Kihlberg、Kristina Luthman
DOI:10.1039/b718058f
日期:——
Analogues of the pyridine based PLG (Pro-Leu-Gly-NH2) peptidomimetic 1 were synthesized and evaluated as dopamine modulating agents. Modifications in the position corresponding to the leucine side chain in PLG afforded derivatives 2, 3 and 4, substituted with H, Me and Bn instead of the isobutyl group, respectively. Changes in the proline residue produced derivative 5, substituted with a symmetrical piperidine ring instead of the pyrrolidine ring and 6, in which the pyrrolidine ring is connected to the pyridine ring via a hydroxymethyl group instead of a keto function. The peptidomimetics were tested for their ability to enhance the maximal effect of N-propylapomorphine (NPA) at dopamine D2 receptors in the functional cell-based R-SAT assay. Compounds 2, 3, and 4, produced a statistically significant increase in the maximal NPA response at 10 nM (117 ± 6%, 118 ± 6%, and 116 ± 3%, respectively), which is similar to the effect of PLG in this assay, whereas 5 was able to potentiate the response to a similar extent at 1 nM concentration (115 ± 5%). All derivatives produced a bell-shaped dose–response curve and none of the compounds were active at the D2 receptor alone, which indicates that the mechanism behind the activity of both the pyridine based mimetics 1–6 and PLG is the same. Interestingly, L-Pro-D-Leu-Gly-NH2 was found to be more potent than PLG and produced a 119 ± 1% increase in the NPA response at 1 nM.
我们合成了吡啶基 PLG(Pro-Leu-Gly-NH2)拟肽物 1 的类似物,并将其作为多巴胺调节剂进行了评估。对 PLG 中与亮氨酸侧链相对应的位置进行修改后,得到了分别用 H、Me 和 Bn 取代异丁基的衍生物 2、3 和 4。脯氨酸残基的变化产生了用对称哌啶环取代吡咯烷环的衍生物 5 和吡咯烷环通过羟甲基而不是酮基连接到吡啶环的衍生物 6。在基于功能细胞的 R-SAT 试验中,测试了拟肽物增强 N-丙基吗啡(NPA)对多巴胺 D2 受体最大作用的能力。化合物 2、3 和 4 在 10 nM 浓度下可显著提高 NPA 的最大反应(分别为 117 ± 6%、118 ± 6% 和 116 ± 3%),这与 PLG 在该试验中的效果相似,而化合物 5 在 1 nM 浓度下可在类似程度上增强 NPA 的反应(115 ± 5%)。所有衍生物都产生了钟形的剂量-反应曲线,没有一种化合物单独对 D2 受体有活性,这表明吡啶类拟效剂 1-6 和 PLG 的活性机制是相同的。有趣的是,L-Pro-D-Leu-Gly-NH2 比 PLG 更有效,在 1 nM 的剂量下,NPA 反应增加了 119 ± 1%。