Changes in the brain expression of alpha-2 subunits of the GABA-A receptor after chronic restraint stress in low- and high-anxiety rats

Central relaxin-3 receptor (RXFP3) activation reduces elevated, but not basal, anxiety-like behaviour in C57BL/6J mice

“…Functionally, icv administration in adult Sprague-Dawley rats of the relaxin-3 agonist peptide, 'RXFP3-A2' , which is selective for RXFP3 over RXFP1 [40], reduced anxiety-like behaviour [33]. The precise brain sites influenced by RXFP3 to produce these behavioural changes in the anxiety tests studied are not known, but it might involve activation of RXFP3 strongly expressed within areas involved in aversion-motivated exploration such as the extended amygdala, the periaqueductal grey and hippocampus [29,[41][42][43].…”

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 rats were then exposed to 21 sessions of chronic restraint stress (29 days, with a break on the weekends) in restraint hemicylinders for 3 h per session with one session per day as previously described in detail [28]. The control groups remained in their home cages, and these rats were only handled for 5 min per day (Fig.…”

“…1A). Chronic restraint stress decreased rat activity in the Porsolt test and reduced body weight more in the HR group [28]. On the last day, 48 h after the last immobilisation session 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.…”

“…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.…”