A NEW APPROACH TO THE LIGHT DARK TEST PROCEDURE IN MICE/

The effect of the known anxiolytic agents diazepam and alprazolam and a putative anxiogenic agent, FG 7142, were assessed in a fully automat ed and computer-integrated two-compartment light/dark apparatus. In ad dition, psychostimulant drugs (amphetamine, adrafinil, amineptine, and caffeine) were tested to determinate the influence of increasing loco motor activity on the indices of anxiety. Some modifications, such as using a soiled apparatus, have been made from the initial model to red uce any neophobic response to the test situation. These results have b een compared to results obtained after cleaning between trials. In add ition, strain differences have been assessed by comparing the effect o f Swiss mice with the C57B1/6J strain. The role of each parameter as a n index of anxiety is discussed. The time spent in the lit area and ex ploratory behaviors seemed to be the most reliable parameter for asses sing anxiolytic-like activity. Diazepam and alprazolam were found to h ave an anxiolytic profile. FG 7142 did not demonstrate any intrinsic e ffect. Amphetamine was reported to be anxiogenic, and amineptine, adra finil, and caffeine only had a psychostimulant profile. We conclude th at the light/dark test may be useful for identifying putative anxiolyt ic and anxiogenic agents, but an additional test such as an open field or an actimeter test must be performed, as a control with regard to t he problem of sedation and change in exploration. The Swiss strain of mice has been found a suitable strain to be used in the test. (C) 1998 Elsevier Science Inc.