The anxiolytic-like activity of AIDA (1-aminoindan-1,5-dicarboxylic acid), an mGLU 1 receptor antagonist

In the present study we examined the effects of 1-aminoindan-1,5-dicarboxylic acid (AIDA), regarded as a selective and competitive mGluR1 antagonist, in animal models of anxiety. Diazepam (1-10 mg/kg) was used as a reference drug. After intraperitoneal administration, AIDA (0.5-2 mg/kg) produced anxiolytic-like effects in the conflict drinking test and the elevated plus-maze test in rats; however, in doses up to 8 mg/kg, it was inactive in the four-plate test in mice. AIDA tested at the effective doses in the conflict drinking test changed neither the treshold current nor water intake in rats compared to vehicle treatment. AIDA (in a dose of 4 mg/kg, but not lower) increased the exploratory locomotor activity of rats measured in the open-field test, but it did not disturb rat motor coordination in the rota-rod test. The above results indicate that selective mGluR1 antagonist AIDA induces antianxiety-like effects at a low risk of acute side effects characteristic of benzodiazepines. Further studies are required to identify the sites and the mechanism of action of AIDA.