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Updated: Jul 2, 2026
The Forced Swim Test as a Model of Depressive-like Behavior
Published on: March 2, 2015
Antidepressant-like effects of echo-planar magnetic resonance imaging in mice determined using the forced swimming
Elif Aksoz1, Tolga Aksoz, S Sirri Bilge
1Department of Pharmacology, Faculty of Medicine, University of Ondokuz Mayis, Kurupelit, 55139 Samsun, Turkey.
Abstract:
Echo-planar magnetic resonance imaging (EP-MRI), which is novel variant of MRI, is thought to have antidepressant properties in humans and animal models. Using the forced swimming test (FST), we investigated which monoaminergic system in mice is affected by EP-MRI. The short- and long-term effects of EP-MRI on immobility time in the FST and motor activity within a locomotor activity cage were examined. Two groups of mice underwent 20 min of EP-MRI in an MR scanner (Siemens, 1.5 T Symphony) either 23.5 or 1 h before the start of the second session of the FST. In both groups, the immobility duration in the FST was reduced, similar to effective antidepressant drug treatments. Climbing behavior in the 1-h group and swimming behavior in the 23.5-h group increased significantly, similar to that seen after the administration of desipramine (a noradrenaline reuptake inhibitor) and sertraline (a selective serotonin reuptake inhibitor), respectively. The findings support the hypothesis that EP-MRI has an antidepressant-like effect. We suggest that the antidepressant-like effect begins in the early period with noradrenaline systems and is maintained in the late period with serotonin systems.
Insights
Echo-planar magnetic resonance imaging (EP-MRI) shows antidepressant-like effects in mice by reducing immobility. This novel MRI technique impacts both noradrenaline and serotonin systems, suggesting potential therapeutic applications.
Area of Science:
- Neuroscience
- Psychiatry
- Medical Imaging
Background:
- Echo-planar magnetic resonance imaging (EP-MRI) is a novel MRI variant.
- EP-MRI is hypothesized to possess antidepressant properties in both human and animal models.
Purpose of the Study:
- To investigate the specific monoaminergic systems affected by EP-MRI in mice.
- To examine the short- and long-term effects of EP-MRI on depressive-like behaviors and motor activity.
Main Methods:
- Mice underwent 20-minute EP-MRI sessions at different time points before the forced swimming test (FST).
- Behavioral outcomes, including immobility time in FST and locomotor activity, were assessed.
- The study utilized a Siemens 1.5 T Symphony MR scanner.
Main Results:
- EP-MRI significantly reduced immobility duration in the FST, comparable to effective antidepressant drugs.
- Climbing behavior increased in the 1-hour group, mimicking effects of noradrenaline reuptake inhibitors (desipramine).
- Swimming behavior increased in the 23.5-hour group, similar to selective serotonin reuptake inhibitors (sertraline).
Conclusions:
- The findings support the antidepressant-like effect of EP-MRI.
- EP-MRI's antidepressant effects appear to involve noradrenergic systems in the early phase and serotonergic systems in the later phase.
