Dopamine overflow is increased in olfactory bulbectornized rats: an in vivo microdialysis study

Olfactory bulbectomy (OBX) in rats produces behavioral, physiological, and neurochemical changes that resemble symptoms of depression in humans. The procedure thus serves as a rodent model of affective disorder. Many of the behavioral effects of OBX resemble psychomotor agitation. The possible role of dystegulation of ventral striatal dopamine (DA) systems in this phenomencri was investigated. Basal levels of DA, norepmephrine (NE), homovanillic acid, dihydroxyphenyl acetic acid, and 5-hydroxyindoleacetic acid were examined in the striatum of OBX and sham-operated controls using in vivo microdialysis. OBX rats exhibited significantly higher basal DA levels (192%) and lower NE levels (12%) than sham-operated controls. Locomotor activity in response to novelty and footshock stress was elevated in OBX rats. The finding of higher DA levels in striatum may explain this agitation-like behavior, a commonly observed phenomenon in the OBX model. (C) 2004 Elsevier Inc. All rights reserved.