Anxiogenic Effect of Single Swim Session is Reversed by Diazepam in Adult Male Wistar Rats

Background and Objective: Anxiety is a disorder with a high prevalence worldwide that requires further study and the consequences of stressful situations contribute to its development. At the preclinical level, a single swimming session is an intense and inescapable stressor that induces despair and other alterations in hemostasis in rats. This study examined the effect of a single swim session (SS) on the development of anxiety-like behavior and the reversal of the anxiolytic diazepam in the elevated plus maze (EPM) in adult male rats. Materials and Methods: Four groups: Control group that received saline (n = 8) and diazepam group (DZP, 2 mg/kg, n = 7) were not submitted to swimming; SS (n = 8) and SS+DZP (n = 8) swam for 15 min 24 h before EPM. Diazepam or saline was i.p., injected 1 h before the EPM test. The variables evaluated were time in seconds, number of entries and percentage of entries into open arms, anxiety index and total entries in EPM, which were analyzed by one-way analysis of variance. Results: The SS group spent less time on the open arms and had a higher anxiety index, with no changes in total arm entries compared with the control group (i.p., saline, 1 mL/kg, n = 8). The DZP produced the highest time spent in open arms and the lowest anxiety index in rats without swimming. This benzodiazepine in rats submitted to swimming produced a significant anxiolytic effect compared to the SS group but less than DZP alone. Conclusion: These findings indicated that a single 15 min SS session is a potent anxiogenic stimulus in adult male Wistar rats and diazepam blocks this anxiogenic effect. Therefore, the strong stress experience leads to the foresight of working with anxiety-induced animals, impacting basic sciences and conferring perspectives for studying certain types of anxiety with behavioral pharmacology methods.