Forced swimming test; Porsolt test; Tail suspension test Definition
Tests of behavioral despair are used to measure the effects of ► antidepressant drugs on the behavior of laboratory animals (typically rats or mice). Examples of these tests include the forced swimming test (a.k.a., the FST or Porsolt test) and the tail suspension test (TST).
When forced to swim in a restricted space without the possibility of escape, rats and mice will, after a period of vigorous behavior directed toward escape, adopt a characteristic immobile posture, where they remain passively floating in the water, making only those movements necessary to keep their heads above water. The immobility response is usually measured by the latency until development or the overall duration during the session. The immobility in the forced swim test is thought to indicate resignation to a state of despair, in which the rodent has learned that escape is impossible (Porsolt et al. 1977, 1978a). The immobility response is reduced by administration of antidepressant drugs and other treatments that are therapeutically effective in depression.
The tail suspension test was developed later as a second test for use with mice (Steru et al. 1985). Mice that are hung by their tail from a bar will, after some time spent trying to escape, adopt a characteristic immobile position. The test relies on the same behavioral principle as the forced swimming test, since mice are not able to escape from being attached to the bar. Administration of antide-pressant drugs reduces the time spent immobile.
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