[The characteristics of the restructuring of the circadian dynamics in rat motor activity in response to a phase shift in the photoperiod in the experimental modelling of depression].

Gradual reorganization of the locomotor activity of rats after a shift in the photoperiod was disrupted under the influence of depressogenic agents (reserpine or chronic pain stress). After the chronic use of the antidepressant amitriptyline the disruption of the reorganization of the daily motor activity typical for reserpine was not observed confirming a specificity of these changes. The results suggest that in the experimental model of depression there arise conditions for functional disturbance of the circadian pacemaker and an increase of sensitivity to the photic Zeitgeber.