Influence of previous stress exposure on the effects of serotonergic and noradrenergic antidepressants on subsequent newly induced stress is still far from being completely understood. The aim of the present study was to investigate changes in the activity of the sympatho-adrenomedullary system in unstressed and chronic unpredictable mild stressed (CUMS) rats treated with either maprotiline or fluxilan, both under basal conditions and subsequent immobilization stress. Maprotiline and fluxilan elevated plasma norepinephrine in unstressed control and CUMS rats. Immobilization increased norepinephrine less in unstressed maprotiline- or fluxilan controls than in vehicle group. Subsequent immobilization elevated norepinephrine in CUMS rats the differences between the groups being insignificant. Maprotiline didn't affect epinephrine in unstressed and CUMS rats and fluxilan increased it. Subsequent immobilization elevated epinephrine in unstressed maprotiline controls less than in vehicle animals. Epinephrine increase was similar in maprotiline CUMS and vehicle CUMS rats. Immobilization of fluxilan unstressed and CUMS rats significantly increased epinephrine but without differences compared to vehicle group. Novel stressor activated sympatho-adrenomedullary system of CUMS rats upon antidepressants.