Anti-anxiety and sedative profile evaluation of imidazo[1,2-a]pyridine derivatives

(Table Presented) Three imidazo[1,2-a]pyridine-3-nitrosated (L-1, L-2, L-3) and a 3-formyl imidazo[1,2-a]-pyridine thiosemicarbazone (L-4) were synthesized and evaluated for their effects in the elevated plus maze, burying behavior test, rotarod performance, the horizontal wire test, and locomotor activity. L-2 and L-3 increased the percent time spent in the open arms of the plus maze at doses of 1 and 2 mg/kg without modifying the number of total entries. In addition, L-2 and L-3 (1 mg/kg) increased the number of open arm entries indicating anxiolytic-like activity at this dose. In the burying behavioral test, L-1 (2-8mg/kg), L-2 (8mg/kg), and L-3 (4 and 8mg/kg), induced a clear reduction in cumulative burying behavior, without modifying burying behavior latency, thus reducing experimental anxiety. In the rotarod test, L-1 and L-2 impaired rotarod performance only at the highest evaluated dose (64mg/kg) at which reduction of motor activity was observed and thereby no conclusions about myorelaxant effects can be proposed. All compounds showed a clear sedative effect and corresponding ED₅₀ values were obtained. Results indicate that compounds L-1, L-2, and L-3 show a sedative and an anxiolytic profile.