Reversible and non-competitive antagonist profile of CPCCOEt at the human type 1 alpha metabotropic glutamate receptor

In transfected CHO cells expressing the human metabotropic glutamate recept or mGlu1 alpha, 7- hydroxyimino)cyclopropan[b]chromen-1a-carboxylic acid et hylester (CPCCOEt) was found to antagonize L-quisqualate-induced phosphoino sitide hydrolysis in a non-competitive and reversible manner (apparent pK(i ) value, 4.76 +/- 0.18: It = 3. This suggests that CPCCOEt antagonizes type Ir metabotropic glutamate receptor activation by interacting with a site d istinct from the agonist binding site. (C) 1998 Elsevier Science Ltd. All r ights reserved.