Divergent effects of chronic continuous and intermittent social defeat stress on emotional behaviors: Impact on phosphorylated CREB and BDNF protein levels in the rat hippocampus.

Chronic psychosocial stress stands as a significant heterogeneous risk factor for psychiatric disorders. The brain's physiological response to such stress varies based on the frequency and intensity of stress episodes. However, whether stress episodes divergently could affect hippocampal cyclic AMP response element-binding protein (CREB)-brain-derived neurotrophic factor (BDNF) signaling remains unclear, a key regulator of psychiatric symptoms.

Dynamic Changes of Behavioral Despair, HPA Axis Activity, and Hippocampal Neurogenesis in Male Rats Induced by Social Defeat Stress.

Background: Psychosocial stress factors, such as threat and defeat, are major risk factors for the development of depression. The precise mechanisms underlying stress-induced depression are not clearly understood because the stress response in the brain varies in a stress-frequency-dependent manner. In the current research milieu on the pathogenesis of depression, the focus is on depression-like behavioral phenotype, hypothalamic-pituitary-adrenal (HPA) axis, and hippocampal neurogenesis.

Upregulations of α adrenergic receptors and noradrenaline synthases in the medial prefrontal cortex are associated with emotional and cognitive dysregulation induced by post-weaning social isolation in male rats.

Early-life social isolation induces emotional and cognitive dysregulation, such as increased aggression and anxiety, and decreases neuron excitability in the medial prefrontal cortex (mPFC). The noradrenergic system in the mPFC regulates emotion and cognitive function via α or α adrenergic receptors, depending on noradrenaline levels. However, social isolation-induced changes in the mPFC noradrenergic system have not been reported.

Oxytocin treatment improves dexamethasone-induced depression-like symptoms associated with enhancement of hippocampal CREB-BDNF signaling in female mice.

Aims: Chronic stress and glucocorticoid exposure are risk factors for depression. Oxytocin (OT) has been shown to have antistress and antidepressant-like effects in male rodents. However, depression is twice as common in women than in men, and it remains unclear whether OT exerts antidepressant-like effects in women with depression.

Continuous psychosocial stress stimulates BMP signaling in dorsal hippocampus concomitant with anxiety-like behavior associated with differential modulation of cell proliferation and neurogenesis.

Bone morphogenetic protein (BMP) signaling in the hippocampus regulates psychiatric behaviors and hippocampal neurogenesis in non-stress conditions; however, stress-induced changes in hippocampal BMP signaling have not yet been reported. Therefore, we sought to examine whether psychosocial stress, which induces psychiatric symptoms, affects hippocampal BMP signaling. A total of 32 male Sprague-Dawley rats were exposed to a psychosocial stress using a Resident/Intruder paradigm for ten consecutive days.