A Depressive State in Rats in Chronic Combined Stress Induced by Combined Stresses of Different Modalities

Chronic combined stress with substitution of stressors of different modalities (noise, vibration, and pulsating bright light) presented using a stochastic scheme on the background of constant stressors (movement restriction, oscillation in environmental temperature) induced symptoms of depression-like behavior in animals, this displaying marked phenomenological similarity with the clinical picture of depression: anxiety and behavioral correlates – despair, hypodynamia, and anhedonia – as well as the morphosomatic consequences of chronic stress, i.e., involution of the thymus and spleen, hypertrophy of the adrenals, and ulceration of the gastric mucosa. Imipramine and fluoxetine effectively suppressed these behavioral abnormalities and their efficacies were consistent with clinical trials results and data obtained in other models of depression. This model of depression has satisfactory measures of construct and predictive validity and can be used for physiological, ethological, and pharmacological studies.