Changes in blood CD4+T and CD8+T lymphocytes in stressed rats pretreated chronically with desipramine are more pronounced after chronic open field stress challenge.

The present study examines the influence of a chronic (14 consecutive days) desipramine (10mg/kg i.p.) pretreatment by itself vs. after chronic (7 consecutive day) open-field (OF) on immune system alterations in response to acute (30 min) OF in Wistar rats (n=60). Opposing to the effect of desipramine injected alone, the combined pretreatment after chronic OF challenge exerts suppressive effects on peripheral blood T/B, CD4(+)T-helper/inducer and CD8(+)T-cytotoxic/suppressor but not NK cell number, decreased interferon-γ/interleukin-10 ratio and thymus weight in the stressed rats. It suggests that chronic stress exposure is important for the immunomodulatory effects of pretreatment with antidepressants.