An open field study of antidepressant drugs

Eight psychotropic drugs, mainly acting on the catecholaminergic systems, were investigated in an open field setting. All drugs but one showed a significant reduction in overall activity over time. Only piribedil at 32 mg/kg showed an increase, while 2 mg/kg showed a decrease over time. Amineptine and nomifensine significantly increased and salbutamol significantly decreased both ambulation and rearing with dose. For viloxazine, metapramine, piribedil and piracetam no significant dose effects were revealed at the doses tested. It is concluded that no clear correlation between clinically reported antidepressant efficacy and the selected open field variables can be demonstrated. However, some of the dopaminergic drugs have substantial activating properties, which might render them dependence-producing properties.