Adulthood behavioral and neurodevelopmental effects of being raised byan ambivalent mother in rats: what does not kill you makes you stronger.

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 brain-derived 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.

Behavioural and neurobiological consequences of 2 different chronic stressors in rats.

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.