The common brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with reduced activity-dependent BDNF release and increased risk for anxiety disorders and PTSD. Here we behaviorally phenotyped a novel Val66Met rat model with an equivalent valine to methionine substitution in the rat Bdnf gene (Val68Met). In a three-day fear conditioning protocol of fear learning and extinction, adult rats with the Met/Met genotype demonstrated impaired fear memory compared to Val/Met rats and Val/Val controls, with no genotype differences in fear learning or extinction. This deficit in fear memory occurred irrespective of the sex of the animals and was not seen in adolescence (4 weeks of age). There were no changes in open-field locomotor activity or anxiety measured in the elevated plus maze (EPM) nor in other types of memory measured using the novel-object recognition test or Y-maze. BDNF exon VI expression in the dorsal hippocampus was higher and BDNF protein level in the ventral hippocampus was lower in female Val/Met rats than female Val/Val rats, with no other genotype differences, including in total BDNF, BDNF long, or BDNF IV mRNA. These data suggest a specific role for the BDNF Met/Met genotype in fear memory in rats. Further studies are required to investigate gene–environment interactions in this novel animal model.

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Exercise has been shown to be beneficial in reducing symptoms of affective disorders and to increase the expression of brain-derived neurotrophic factor (BDNF). The BDNF Val66Met polymorphism is associated with reduced activity-dependent BDNF release and increased risk for anxiety and depression. Male and female Val66Met rats were given access to running wheels from 3 weeks of age and compared to sedentary controls. Anxiety-and depression-like behaviors were measured in adulthood using the elevated plus maze (EPM), open field (OF), and forced swim test (FST). Expression of BDNF and a number of stress-related genes, the glucocorticoid receptor (Nr3c1), serum/glucocorticoid-regulated kinase 1 (Sgk1), and FK506 binding protein 51 (Fkbp5) in the hippocampus were also measured. Rats given access to running wheels developed high levels of voluntary exercise, decreased open-arm time on the EPM and center-field time in the OF, reduced overall exploratory activity in the open field, and increased immobility time in the FST with no differences between genotypes. Chronic exercise induced a significant increase in Bdnf mRNA and BDNF protein levels in the hippocampus with some of these effects being genotype specific. Exercise decreased the expression of Nr3c1 and Sgk1, but increased the expression of Fkbp5. These results suggest that chronic running-wheel exercise from adolescence increased anxiety and depression-like phenotypes in adulthood, independent of BDNF Val66Met genotype.Further studies are required to confirm that increased indices of anxiety-like behavior are independent from reduced overall locomotor activity.

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Objectives Global pandemics, such as the current COVID‐19 pandemic, are predicted to increase in prevalence in the future. Transmission suppression techniques such as social distancing and stay‐at‐home restrictions have introduced an abundance of additional stressors while simultaneously reducing our capacity to cope with stress, thus increasing the collective burden of the pandemic. Numerous psychosocial factors have been identified to protect against distress in difficult circumstances. However, it is unknown whether these factors will continue to be protective in the pandemic context. Design The aim of the current study was to determine whether locus of control (LOC), coping style or self‐compassion were debilitating or protective factors towards psychological well‐being (depression, anxiety, stress and positive and negative affect) during the COVID‐19 pandemic. Methods In the current study, Australian adults (N = 176) completed a longitudinal online survey (two time points, 2 weeks apart) incorporating measures of demographics, locus of control, coping, self‐compassion (measured at T1), depression, anxiety, stress and positive and negative affect (measured at T1 and T2) throughout June–August 2020, during the height of lockdown in Australia. Results Multiple regression analyses suggested that avoidant coping was predictive of increases in stress and negative affect across time points. Additionally, self‐compassion was predictive of increased positive affect across time points. Conclusions These results suggest that the pandemic context represents a unique stressor, demanding a distinctive set of strategies and psychosocial characteristics to cope. Interventions targeted at reducing avoidant coping behaviours and promoting self‐compassion may contribute to improvements in psychological well‐being during the COVID‐19 pandemic as well as future pandemics.