The effect of depression in an animal model on 5'-ectonucleotidase, antibody production, and tissue ascorbate stores

The learned helplessness model of depression in rats was tested. It was hypothesized that 5'-ectonucleotidase (NT), ascorbate, and antibody to sheeps' red blood cells (SRBC) are significantly reduced in rats who experienced uncontrollable shock, compared with rats who did not receive shock or could control it. During a learned-helplessness manipulation, antibody response to SRBC and NT values were unaffected. However, tissue ascorbate stores fell significantly, by 20-30%. The lack of effects on antibody responses and NT are discussed n terms of the acute nature of the stressor used in this model, as opposed to the more chronic stressors that have occurred in the human model.