Ondansetron, gender and antipredator defensive behaviour

Area of Science:

• Neuroscience
• Behavioral Pharmacology
• Animal Behavior

Background:

• The 5-HT(3) receptor antagonist ondansetron has shown inconsistent effects in animal models of anxiety.
• Ethological test batteries are valuable tools for assessing anxiety and fear responses in rodents.

Purpose of the Study:

• To evaluate the efficacy of ondansetron in reducing anxiety and fear behaviors in rats using two distinct ethological test batteries.
• To investigate potential gender differences in defensive behaviors in response to threat stimuli.

Main Methods:

• Utilized the Fear/Defense Test Battery (F/DTB) with wild-trapped rats and the Anxiety/Defense Test Battery (A/DTB) with laboratory rats.
• Assessed behavioral reactions to human threat (F/DTB) and cat-related stimuli (A/DTB) after ondansetron administration (0.001-0.10 mg/kg).

Main Results:

• Ondansetron failed to produce consistent anxiety or fear reduction in either the F/DTB or A/DTB.
• A significant gender difference emerged in the F/DTB, with female rats exhibiting greater defensiveness than males.

Conclusions:

• Ondansetron's anxiolytic or anti-fear effects in these specific ethological models are not supported.
• The study highlights the importance of considering gender when assessing defensive behaviors in rats, particularly in wild-trapped populations.