Stressor-induced alterations in serotonergic activity in an animal model of depression

Examined the effect of 2 neurogenic stressors (air puff and restraint) and a metabolic stressor (lipopolysaccharide; 100 ?g/kg) on accumbal serotonergic neurotransmission in the olfactory bulbectomized (OB) rat model of depression. Male Sprague-Dawley rats were used in 2 studies. Both puff and restraint stress caused greater increases in accumbal 5-hydroxyindoleacetic acid (5-HIAA) in OB vs sham-operated rats. In contrast, bulbectomy resulted in a blunted serotonergic response to a challenge with the metabolic stressor. In addition, OB rats displayed significantly basal levels of 5-HIAA than sham-operated Ss, a finding consistent with previous reports of the OB rat being a model of hyposerotonergic depression. The relevance of these findings to stressor-provoked depressive-like behaviors in the OB rat is discussed.