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

Chronic restraint increases apoptosis in the hippocampus of rats with high responsiveness to fear stimuli

“…We demonstrated that HR rats under stressful conditions adopt an avoidance strategy more often than LR animals (which is expressed, for example, as a longer freezing time during the conditioned fear test and increased immobility time during the Porsolt test) and are more susceptible to stressful environmental challenges [9][10][11] C. Freezing response -chronic corticosterone This study examined the effects of chronic restraint stress and corticosterone treatment on apoptosis-related processes in the dentate gyrus of the rat hippocampus and compared rats with different fear-conditioned response strengths. The behavioural data obtained from the same groups of animals have been previously published [23,28]. These publications demonstrate that HR rats exposed to chronic restraint and corticosterone had increased immobility times during the Porsolt test and enhanced anxietylike behaviour (a decreased anti-thigmotactic index in the open field test) compared with LR rats.…”

“…The conditioned fear was tested on the 3rd day (test day) by re-exposing rats to the testing box and recording their freezing response for 10 min. Freezing was measured by infra-red photo beams with a 10 Hz detection rate controlled by fear conditioning software (TSE, Bad Homburg Germany) [23,28]. According to the duration of their context-induced freezing responses during the Conditioned Freezing Test (10 min long) [28], the animals were divided into a low anxiety (LR) group (comprised of rats with a total freezing response duration of one SEM or more below the mean (260.17-21.8 s, i.e., <238.37)) and a high-anxiety (HR) group (comprising rats with a total freezing response duration of one SEM or more above the mean (260.17 + 21.8 s, i.e., >281.97)) (Fig.…”

“…Male Wistar adult rats (6-8 weeks old) from the stock of the Centre for Experimental Medicine, Medical University of Białystok, Poland, were housed under standard laboratory conditions. The rats were also divided into LR (265.04-24.95, i.e., <240.09) and HR groups (265.04 + 24.95, i.e., >289.99) [23] according to the duration of their context-induced freezing responses (Fig. 1C).…”

“…The control groups received vehicle injections (1 ml/kg sesame oil). Chronic corticosterone increased rat immobility in the Porsolt test and reduce body weight more in the HR group [23]. On the last day, 48 h after the last corticosterone injection and 45 min after the test session of the Porsolt test was conducted, the animals were decapitated and their brains were removed and frozen at −70 • C for immunochemistry.…”

Anti-stress Effects of 20(<i>S</i>)-Protopanaxadiol and 20(<i>S</i>)-Protopanaxatriol in Immobilized Mice

“…[3][4][5][6] Glucocorticoids also alter the uptake and release of GABA, decrease benzodiazepine receptor binding in the hippocampus and amygdala, and attenuate 5-HT 1A receptor function, which induced anxiety-like behaviors in animal models. [28][29][30] Ginseng has been traditionally used for the treatment of psychiatric disorders, such as anxiety and depression: it attenuates stress-induced corticosterone and IL-6 by regulation of cortical cells of adrenal and pituitary adrenocorticotrophic hormone (ACTH) secretion and induces anxiolytic-like effects in the elevated plus-maze (EPM) test in mice. [31][32][33][34][35] Of its constituents, ginsenosides Rb1, Rh2, Rg5/Rk mixture, and Rg1 also showed an anxiolytic effect (i.e., mice treated with these ginsenosides increased the time spent in the open arm (OT) or open arm entries (OE) in the EPM test).…”