Escitalopram improves memory deficits induced by maternal separation in the rat

Maternal separation (MS) induces depressive-like behavior and long-term changes in cognition in rats. Escitalopram is an antidepressant drug shown to reverse the depressive-like features caused by this stress model. However, it is not known if it can ameliorate the affected cognition. We now characterized the effect of escitalopram on hippocampal-dependent memory in rats submitted to the MS protocol. Male Wistar rats were assigned either to control (CTR) or maternal separated (MS) group. MS were separated from their dams between 2-14 postnatal days (PND) for 180min daily. Escitalopram was given in food pellets (0.34g/kg/day first 2 weeks and 0.41g/kg/day the subsequent period, average dose 25mg/kg) from PND 43 onwards, during 1 month. Depressive behavior was assessed in the forced swimming test (FST), and memory performance in the Morris water maze (MWM). Escitalopram significantly improved the FST's latency to despair in the MS group (n=6), but did not change the immobility time. All groups showed a significant learning effect in the MWM over time, but no differences have been found upon treatment (n=6). However, escitalopram treatment significantly increased the time spent on the platform quadrant in the probe trial in the MS group. We report here that chronic treatment with escitalopram is able to improve hippocampal dependent memory in a chronic stress model, while not changing the learning ability. Moreover, this is accompanied by an amelioration of the depressive like behavior. These results support the use of escitalopram to tackle underlying cognitive deficits caused by stress in early-life.