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 wa s hypothesized that 5'-ectonucleotidase (NT), ascorbate, and antibody to sheeps' red blood cells (SRBC) are significantly reduced in rats wh o experienced uncontrollable shock, compared with rats who did not rec eive shock or could control it. During a learned-helplessness manipula tion, antibody response to SRBC and NT values were unaffected. However , tissue ascorbate stores fell significantly, by 20-30%. The lack of e ffects on antibody responses and NT are discussed in terms of the acut e nature of the stressor used in this model, as opposed to the more ch ronic stressors that have occurred in the human model.