This is one of the first publications reporting the results of original research performed in an EQIPD-certified laboratory. This study was conducted in the Department of Behavioral Neuroscience and Drug Development (Head: Professor Piotr Popik). The EQIPD Quality System ensures the implementation of critical quality measures according to EQIPD expectations (like carefully designing the study in advance with prespecifying inclusion and exclusion criteria, blinding and randomization procedures as well as proper study documentation at every stage of the research progress).
The aims of the present study by Natalia Malikowska-Racia and colleagues were to directly compare the performance of rats treated with ketamine enantiomers in DRL 72-s to examine their antidepressant-like actions and effects on timing. SSRI fluoxetine was used as a “positive” control.
(S)-ketamine-induced rapid-acting antidepressant effects have revolutionized the pharmacotherapy of major depression; however, this medication also produces psychotomimetic effects such as timing distortion.
The other goal of the study was to investigate the effects of opioid receptors blockade on the antidepressant-like effects of ketamine enantiomers and of fluoxetine.
The authors found, while all tested medications produced antidepressant-like effects in DRL 72-s, fluoxetine- and (S)- but not (R)- ketamine-induced time underestimation (the subject experiences the time as passing quickly). The potentiation of DRL performance of fluoxetine by naloxone was unexpected and warrants clinical studies.

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