Acute stress‐induced sensitization of the pituitary-adrenal response to heterotypic stressors: Independence of glucocorticoid release and activation of CRH1 receptors

► A single immobilization (IMO) causes long-lasting sensitization of ACTH response to a heterotypic stressor. ► Huge activation of the hypothalamus-pituitary-adrenal (HPA) axis by metyrapone did not induce heterotypic sensitization. ► IMO-induced HPA sensitization is not altered after blockade of IMO-induced glucocorticoid release. ► Activation of GR and CRH type 1 receptors plays no role in IMO-induced HPA sensitization.