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In rats, hormonal fluctuations during the estrus cycle may have numerous behavioral and neurobiological consequences. The aim of this study was to investigate the effects of estrus cycles and citalopram on behavior, ultrasonic vocalizations, anxiety levels, and c-fos expression in rats. With this aim, the rats were grouped into two: (1) a control group (n=16) and (2) a citalopram group (n=16), which received daily intraperitoneal 20mg/kg citalopram from baseline (D0) to the 10th day (D10). Behavioral analysis and ultrasonic vocalization (USV) recordings were made on D0 and D10. Next, the rats were further subgrouped according to estrus phases identified through a vaginal smear (8 proestrus rats and 8 non-proestrus rats, in each group). The rat's anxiety levels were analyzed with an elevated plus maze (EPM), and their c-fos expression was measured at the cingulate cortex, the amygdala, and the paraventricular thalamic nucleus. Our results showed that the citalopram group showed significantly more grooming behaviors on D10 than the control group (p=0.002). USVs on D0, D10 and during the EPM did not show any significant differences between the groups. Proestrus rats in the control group showed significantly less anxiety-like behavior during the EPM than the non-proestrus rats in the control group (p=0.028 for time spent in open arms, and p=0.011 for entries into open arms). There was no significant difference in anxiety-like behavior between the control and citalopram groups, and between the proestrus and non-estrous rats in the citalopram group. C-fos expression at the amygdala (p=0.013) and the paraventricular thalamic nucleus (p=0.014) was significantly inhibited in the citalopram group. We concluded that estrus cycles have a significant effect on anxiety levels in rats, which may be suppressed behaviorally and neurobiologically by citalopram., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background/aim: To compare the behavioural and neurobiological consequences of chronic headache and chronic mild stress (CMS) in rats., Materials and Methods: Forty-eight male Wistar rats were divided into 4 groups: 1) control group, 2) chronic headache group, 3) CMS group, and 4) sham group. Their behaviour prior to (D0) and after (D14) chronic stress was analysed. Afterwards, they were exposed to the Elevated Plus Maze (EPM) in order to evaluate anxiety-like behaviour and the Forced Swim Test (FST) for observation of depressive-like behaviour. Ultrasonic vocalisations (USVs) were recorded by a USV detector system at DO and D14 and during the FST. The c-fos expressions in various brain regions were analysed 2 h after the EPM and FST., Results: The control group showed significantly more sleeping behaviour at D14 (χ2 = 8.213, P = 0.042), emitted more negative and positive affect USVs at D14 (χ2 = 9.853, P = 0.020) and during FST (χ2 = 4.000, P = 0.046) than the chronic headache and CMS groups, and showed significantly less anxiety-like behaviour in the EPM than the CMS group (P = 0.021)., Conclusion: These results suggest that CMS increases anxiety-like behaviour but not depressive-like behaviour, while chronic headache does not have a significant effect on these behaviours in rats.

Background/aim: This study aimed to investigate the effects of early adverse life events and being raised by an ambivalent mother on rats. Materials and methods: The rats were separated into four groups: 1) the control group (n = 12), which was raised under standard care; 2) the early handling (EH) group, which was raised using an EH model (n = 16); 3) the early deprivation (ED) group, which was raised using an ED model (n = 13), and 4) the ambivalent mother (AM) group, which spent 3 h/day with a "fake mother" (n = 17). When they became adults, their anxiety levels, depressive-like behaviors, and memory functions were measured using the elevated plus maze test, the forced swim test, and the novel object recognition test, respectively. Their neurodevelopment was evaluated by measuring the brainderived neurotrophic factor (BDNF) levels in the prefrontal cortex, the dentate gyrus, and the cerebellum via ELISA. Results: The rats in the ED and AM groups exhibited less anxiety and depressive-like behavior than those in the control and EH groups, particularly in females. There was no significant difference between the groups in memory function or brain BDNF levels. Conclusion: Severe and ambivalent early adverse life events may decrease anxiety and depressive-like behavior in adult rats. [ABSTRACT FROM AUTHOR]