Augmentative therapies do not potentiate the antidepressant-like effects of deep brain stimulation in rats

BackgroundClinical trials have shown promising results with the use of subcallosal cingulate gyrus deep brain stimulation (DBS) for treatment-resistant depression. However, strategies to manage patients who do not respond to this therapy have not been explored in detail. In rats, DBS in the ventromedial prefrontal cortex (vmPFC) induces a significant antidepressant-like response in the forced swim test (FST). We have used this test to investigate potential interactions between DBS and clinically used augmentative regimens.MethodsRats undergoing the FST were treated with vmPFC DBS along with different augmentative drugs, namely buspirone, risperidone and pindolol. Locomotor activity was tested in an open field.ResultsDBS induced a significant reduction in immobility scores as compared to saline treated controls. These antidepressant-like effects, however, were not potentiated by the co-administration of buspirone, risperidone or pindolol.LimitationsDespite having good predictive validity, animal models are limited from a translational perspective.ConclusionsOur results indicate that that the antidepressant-like effects of vmPFC DBS in the FST are not enhanced by augmentative therapies.