Journal of Neural Transmission

, Volume 120, Issue 1, pp 169–176 | Cite as

Differential adaptation of REM sleep latency, intermediate stage and theta power effects of escitalopram after chronic treatment

  • Szilvia Vas
  • Zita Kátai
  • Diána Kostyalik
  • Dorottya Pap
  • Eszter Molnár
  • Péter Petschner
  • Lajos Kalmár
  • György Bagdy
Basic Neurosciences, Genetics and Immunology - Original Article


The effects of the widely used selective serotonin reuptake inhibitor (SSRI) antidepressants on sleep have been intensively investigated. However, only a few animal studies examined the effect of escitalopram, the more potent S-enantiomer of citalopram, and conclusions of these studies on sleep architecture are limited due to the experimental design. Here, we investigate the acute (2 and 10 mg/kg, i.p. injected at the beginning of the passive phase) or chronic (10 mg/kg/day for 21 days, by osmotic minipumps) effects of escitalopram on the sleep and quantitative electroencephalogram (EEG) of Wistar rats. The first 3 h of EEG recording was analyzed at the beginning of passive phase, immediately after injections. The acutely injected 2 and 10 mg/kg and the chronically administered 10 mg/kg/day escitalopram caused an approximately three, six and twofold increases in rapid eye movement sleep (REMS) latency, respectively. Acute 2-mg/kg escitalopram reduced REMS, but increased intermediate stage of sleep (IS) while the 10 mg/kg reduced both. We also observed some increase in light slow wave sleep and passive wake parallel with a decrease in deep slow wave sleep and theta power in both active wake and REMS after acute dosing. Following chronic treatment, only the increase in REMS latency remained significant compared to control animals. In conclusion, adaptive changes in the effects of escitalopram, which occur after 3 weeks of treatment, suggest desensitization in the function of 5-HT1A and 5-HT1B receptors.


SSRI Escitalopram Rapid eye movement (REM) sleep 5-HT1A receptor Intermediate stage of sleep Chronic treatment 



This work was supported by the 6th Framework Program of the European Community LSHM-CT-2004-503474, Hungarian Research Fund Grant T020500, Ministry of Welfare Research Grant 460/2006, TAMOP-2.2.1. B-09/1/KMR-2010-0001(G.B.).

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Szilvia Vas
    • 1
  • Zita Kátai
    • 1
  • Diána Kostyalik
    • 1
  • Dorottya Pap
    • 1
  • Eszter Molnár
    • 1
  • Péter Petschner
    • 1
  • Lajos Kalmár
    • 2
  • György Bagdy
    • 1
    • 3
    • 4
  1. 1.Department of PharmacodynamicsSemmelweis UniversityBudapestHungary
  2. 2.Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of SciencesBudapestHungary
  3. 3.Group of NeurochemistryHungarian Academy of SciencesBudapestHungary
  4. 4.Group of NeuropsychopharmacologyHungarian Academy of SciencesBudapestHungary

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