Synthesis and pharmacological evaluation of new arylpiperazines N-[4-[4-(aryl) piperazine-1-yl]-phenyl]-amine derivatives: putative role of 5-HT1A receptors.

In an attempt to design novel 5-HT(1A) agonists/partial agonists, based on an arylpiperazine nucleus, a series of N-{4-[4-(aryl)piperazine-1-yl]-phenyl}-amine derivatives were synthesized and biologically tested. The anxiolytic effect of the compounds was investigated employing the Elevated plus Maze (EPM) task. On the basis of in vivo functional test, compound 1c (3mg/kg) and 4c (3mg/kg) induced significant increments in open arm entries and time on EPM as compared to Buspirone. The anxiolytic effects of compounds 1c and 4c were effectively antagonized by WAY-100635, a 5-HT(1A) receptor antagonist (0.5mg/kg). Furthermore, we have also evaluated the concentration of 5-HT in the brain tissue using HPLC with fluorescent detection. Our result showed that serotonin levels were significantly decreased by approximately 38% (p<0.001) and approximately 32% (p<0.001) after acute administration of compounds 1c and 4c, respectively. These findings suggest that the anxiolytic like activity of these new arylpiperazines is mediated via 5-HT(1A) receptors in the brain.