Social instigation and repeated aggressive confrontations in male Swiss mice: analysis of plasma corticosterone, CRF and BDNF levels in limbic brain areas

Abstract

Introduction: Agonistic behaviors help to ensure survival, provide advantage in competition, and communicate social status. The resident-intruder paradigm, an animal model based on male intraspecific confrontations, can be an ethologically relevant tool to investigate the neurobiology of aggressive behavior. Objectives: To examine behavioral and neurobiological mechanisms of aggressive behavior in male Swiss mice exposed to repeated confrontations in the resident intruder paradigm. Methods: Behavioral analysis was performed in association with measurements of plasma corticosterone of mice repeatedly exposed to a potential rival nearby, but inaccessible (social instigation), or to 10 sessions of social instigation followed by direct aggressive encounters. Moreover, corticotropin-releasing factor (CRF) and brain-derived neurotrophic factor (BNDF) were measured in the brain of these animals. Control mice were exposed to neither social instigation nor aggressive confrontations. Results: Mice exposed to aggressive confrontations exhibited a similar pattern of species-typical aggressive and non-aggressive behaviors on the first and the last session. Moreover, in contrast to social instigation only, repeated aggressive confrontations promoted an increase in plasma corticosterone. After 10 aggressive confrontation sessions, mice presented a non-significant trend toward reducing hippocampal levels of CRF, which inversely correlated with plasma corticosterone levels. Conversely, repeated sessions of social instigation or aggressive confrontation did not alter BDNF concentrations at the prefrontal cortex and hippocampus. Conclusion: Exposure to repeated episodes of aggressive encounters did not promote habituation over time. Additionally, CRF seems to be involved in physiological responses to social stressors.

Gut-Brain Axis: Probiotic,Bacillus subtilis, Prevents Aggression via the Modification of the Central Serotonergic System

“…The value of circulating cortisol (or CORT) has been used as a criterion of stress response in humans and various animals [115][116][117]. Corticotrophinreleasing factor facilitates aggression [118,119], and related elevation of CORT (or cortisol) also affects neuroendocrine functions through binding to their receptors [120,121], causing neuron loss in the hippocampus [122], dysfunction of the serotonergic system [123], and inhibition of immunity (increased pro-inflammatory cytokines as neuroinflammatory response) within stress-sensitive brain regions [124]. These changes finally lead to the development of psychological disorders such as aggression [109,125].…”

Steroid hormones in hair reveal sexual maturity and competition in wild house mice (Mus musculus domesticus)

“…In comparison, dominant males received very few injuries 40 . In addition, males repeatedly exposed to aggressive confrontations showed significantly elevated plasma corticosterone concentrations 41 .…”

Corticotropin Releasing Factor Mediates KCa3.1 Inhibition, Hyperexcitability, and Seizures in Acquired Epilepsy

“…ELISA. Expression of CRF protein was measured in hippocampal tissue of non-SE and post-SE rats using Rat CRF ELISA kit and following manufacturer's instructions (catalog #MBS269052) (Delawary et al, 2010;Fortes et al, 2017). Each rat provided two hippocampi, which were homogenized in 0.01 M PBS followed by centrifugation at 7500 rpm.…”