title: The effect of chronic administration of corticosterone on anxiety- and depression-like behavior and the expression of GABA-A receptor alpha-2 subunits in brain structures of low- and high-anxiety rats.
abstract: The aim of this study was to examine changes in rat emotional behavior and determine differences in the expression of GABA-A receptor alpha-2 subunits in brain structures of low- (LR) and high-anxiety (HR) rats after the repeated corticosterone administration. The animals were divided into LR and HR groups based on the duration of their conditioned freezing in a contextual fear test. Repeated daily administration of corticosterone (20 mg/kg) for 21 days decreased activity in a forced swim test, reduced body weight and decreased prefrontal cortex corticosterone concentration in both the LR and HR groups. These effects of corticosterone administration were stronger in the HR group in comparison with the appropriate control group, and compared to LR treated and LR control animals. Moreover, in the HR group, chronic corticosterone administration increased anxiety-like behavior in the open field and elevated plus maze tests. The behavioral effects in HR rats were accompanied by a decrease in alpha-2 subunit density in the medial prefrontal cortex (prelimbic cortex and frontal association cortex) and by an increase in the expression of alpha-2 subunits in the basolateral amygdala. These studies have shown that HR rats are more susceptible to anxiogenic and depressive effects of chronic corticosterone administration, which are associated with modification of GABA-A receptor function in the medial prefrontal cortex and basolateral amygdala. The current data may help to better understand the neurobiological mechanisms responsible for individual differences in changes in mood and emotions induced by repeated administration of high doses of glucocorticoids or by elevated levels of these hormones associated with chronic stress or affective pathology.
authors.affiliation: Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957 Warsaw, Poland. Electronic address: skorzews@ipin.edu.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Skórzewska
authors.affiliation: Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957 Warsaw, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Lehner
authors.affiliation: Department of Experimental and Clinical Pharmacology, Medical University, 26/28 Krakowskie Przedmieście Street, 00-927 Warsaw, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Wisłowska-Stanek
authors.affiliation: Department of Experimental and Clinical Pharmacology, Medical University, 26/28 Krakowskie Przedmieście Street, 00-927 Warsaw, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Krząścik
authors.affiliation: Department of Applied Physiology, Mossakowski Medical Research Centre Polish Academy of Science, 5 Pawinskiego Street, 02-106 Warsaw, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ziemba
authors.affiliation: Department of Neurochemistry, Institute of Psychiatry and Neurology, 9 Sobieskiego Street, 02-957 Warsaw, Poland; Department of Experimental and Clinical Pharmacology, Medical University, 26/28 Krakowskie Przedmieście Street, 00-927 Warsaw, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Płaźnik
mesh_terms: D000679:Amygdala / Q000378:metabolism / Q000502:physiology; D000818:Animals; D001007:Anxiety / Q000235:genetics / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects*; D003345:Corticosterone / Q000378:metabolism / Q000494:pharmacology*; D003863:Depression / Q000523:psychology*; D004644:Emotions / Q000502:physiology; D005239:Fear / Q000523:psychology; D007150:Immunohistochemistry; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D017397:Prefrontal Cortex / Q000378:metabolism / Q000502:physiology; D051381:Rats; D011963:Receptors, GABA-A / Q000096:biosynthesis*; D013550:Swimming / Q000523:psychology; D015430:Weight Gain / Q000187:drug effects
chemical_list: C520011:Gabra2 protein, rat; D011963:Receptors, GABA-A; D003345:Corticosterone
keywords: Anxiety; Brain structures; Chronic corticosterone; Depression; GABA-A receptor alpha-2 subunits; Individual differences