The hypothalamic–pituitary–adrenal (HPA) axis plays an important role in the adaptation of the organism to stress. Because of a key role of neuroendocrine system in response to a stressful situation, as well as a significant impact of stress on neuronal plasticity, in this work we investigated how chronic restraint stress (CRS: 2 hours × 14 days) affected the protein levels of BDNF in the prefrontal cortex (PFC), as well as the concentration of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in the plasma. In addition, the aim of this study was to determine a possible correlation between levels of BDNF in the PFC and plasma CORT levels of animals exposed to CRS. We found that CRS increases levels of prefrontal BDNF protein by 25% and levels of CORT by 280%, but decreases levels of ACTH by 18%. Also, we recorded a low, but significant positive correlation between prefrontal BDNF levels and concentrations of CORT in the plasma of chronically stressed rats. Our data confirm that prefrontal BDNF might be an important regulator involved in the adaptive strategy of the HPA axis to maintain adequate reactivity in stress conditions provoked by CRS.

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