Substituent effects of N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamides on positive allosteric modulation of the metabotropic glutamate-5 receptor in rat cortical astrocytes
Substituent effects of N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamides on positive allosteric modulation of the metabotropic glutamate-5 receptor in rat cortical astrocytes
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DOI：
10.1021/jm051252j
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发表时间：
2006-06-01
影响因子：
7.3
通讯作者：
Conn, P. Jeffrey
中科院分区：
文献类型：
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作者：
de Paulis, Tomas;Hemstapat, Kamondanai;Conn, P. Jeffrey
CDPPB[3-氰基-N-(1，3-二苯基-1H-吡唑-5-基)苯甲酰胺]最近被认为是第一个中枢活性的正变构调节剂，它是大鼠和人类代谢性谷氨酸受体(MGluR)mGluR(5)亚型的第一个中枢活性正变构调节剂。我们通过对50个CDPPB类似物的评估，探讨了在培养的大鼠星形胶质细胞中，增强谷氨酸诱导的mGluR5钙释放的结构要求，以及增加对变构拮抗剂结合部位的亲和力。在荧光钙分析中，CDPPB在增强mGluR(5)介导的皮层星形胶质细胞反应中的EC50值为77+/-15 nM，在取代表达大鼠mGluR5的HEK-293细胞膜上的[H-3]甲氧基PEPy结合时的K-I值为3760(430 NM)。构效关系表明，CDPPB的苯甲酰胺部分对位上的电负性芳香取代基提高了活性。1-苯环邻位上的卤素原子进一步提高了结合活性和功能活性。这些取代作用与MPEP[2-甲基-6-(苯乙炔基)-吡啶]芳环中的拮抗剂变构结合部位的作用不匹配。最佳取代基和芳香族位置的结合使得4-nitro-N-(1-(2-fluorophenyl)-3-phenyl-1H-pyrazol-5-yl)苯甲酰胺(VU-1545)在结合和功能分析中分别显示K-I)156(29 NM)和EC50(9.6)(1.9 nM)。
CDPPB [3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide] was recently described as the first centrally active, positive allosteric modulator of rat and human metabotropic glutamate receptor (mGluR) mGluR(5) subtype. We explored the structural requirements for potentiation of glutamate-induced calcium release in naturally expressed mGluR5 in cultured rat astrocytes and increasing affinity for the allosteric antagonist binding site by evaluating 50 analogues of CDPPB. In the fluorometric calcium assay, CDPPB exhibited an EC50 value of 77 +/- 15 nM in potentiating mGluR(5)-mediated responses in cortical astrocytes and a K-i value of 3760 ( 430 nM in displacing [H-3] methoxyPEPy binding in membranes of cultured HEK-293 cells expressing rat mGluR5. The structure-activity relationships showed that electronegative aromatic substituents in the para-position of the benzamide moiety of CDPPB increase potency. Both binding and functional activities were further increased with a halogen atom in the ortho-position of the 1-phenyl ring. These effects of substitution do not match those of either aromatic ring of MPEP [2-methyl-6-(phenylethynyl)-pyridine] for the antagonist allosteric binding site. Combination of the optimal substituents and aromatic positions resulted in 4-nitro-N-(1-(2-fluorophenyl)-3-phenyl-1H-pyrazol-5-yl) benzamide (VU-1545) showing K-i) 156 (29 nM and EC50) 9.6 (1.9 nM in the binding and functional assays, respectively.