Thrivikraman-5P50MH058922-050002

It is suggested that the stress induced activation of the HPA axis and associated increases in plasma ACTH and glucocorticoids (corticosterone, B in the rat) are contributing factors in the development of many psychopathologies. However, the circadian fluctuation of the HPA axis activity (characterized by a zenith in the plasma ACTH and B, before the beginning of the active awake state and the nadir during the inactive sleeping period) occurs throughout the life and is important for normal physiological and behavioral functioning. A blunting or enhancement of this rhythm through changes in the trough or in the peak is a characteristic feature of many pathological states. At the CNS level, the circadian fluctuation of the HPA axis activity is associated with changes in the expression profile of structural, functional, and immediate early genes. However, little is known about the specific role of B in the modulation of the circadian pattern of gene regulation in the CNS.

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