The Protectıve Role of Escıtalopram on Impared Hıppocampal Neuroplastıcıty Durıng Rem Deprıvatıon

Abstract

Sleep disorders are mostly associated with psychiatric problems like depression, anxiety disorders, etc. and are thought to be the underlying cause of cognitive deficits observed in these patients. It has been shown that isolated REM (Rapid Eye Movement) deprivation markedly impairs learning and neuronal functions. Areas related with learning such as hippocampus significantly affected by sleep disturbances. EEG studies recorded from depressive patients exhibit a similar pattern with that of REM deprivation (REMD). Serotonine reuptake inhibitors was shown to reverse the cognitive functional impairments in depressive patients. Therefore, we investigated the protective effects of escitalopram (ESC) on learning impairment induced by REM deprivation. In this study, REMD decreased the excitability of CA1 neuron firing and shifted EPSP slope I/O curve to the right. Paired-pulse stimulation as a measure of short-term placticity, was not altered by REMD or ESC. However, REMD significantly reduced LTP (Long Term Potentiation). In behavioral studies, REM-deprivated rats exhibited impaired learning in place recognition test, reduced anxiety in elevated plus arm maze, and increased locomotor activity in open field test. All these electrophysiological and behavioral changes were absent in chronicaly ESC administrated (2 weeks) animals. REMD and/or ESC did not change the neurotransmitter levels in hippocampi, cortex, hindbrain. In conclusion, 2 weeks of ESC treatment protected the rats from the learning impairment and reversed back the anxiety, locomotor level changes.