Photocopying permitted by license only Pharmacological Suppression of Corticosterone Secretion in Response to a Physical Stressor Does not Prevent the Delayed Persistent Increase in Circulating Basal Corticosterone Concentration

Abstract

Elevated basal plasma corticosterone concentrations have been observed for several days after the cessation of severe stress. In the present study, we examined whether or not the acute plasma corticosterone response to stress is necessary to elicit increased basal plasma corticosterone concentrations the following day. Pretreatment with metyrapone (100 mg/kg, intraperitoneal) 1 h before inescapable stress (40 2mA tailshocks delivered over a 1-h period) (IS) blocked the acute plasma corticosterone response to IS. However, elevated basal plasma corticosterone concentrations still emerged the next day. These results suggest that the corticosterone response to stress, and its attendant feedback, are not necessary to produce persistent hypothalamic-pituitary-adrenal axis (HPAA) activation.