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Updated: Oct 2, 2026
The Mouse Forced Swim Test
Published on: January 29, 2012
Progesterone reduces immobility in rats forced to swim
L Martínez-Mota1, C M Contreras, M Saavedra
1Laboratorio de Neurofarmacología, Universidad Veracruzana, Xalapa, Veracruz, Mexico.
Background:
Among its behavioral actions, progesterone reduces anxiety in several species including humans; however, any antidepressant-like properties remain to be explored.
Methods:
In the present study, Wistar rats received injections (i.p.) of progesterone (0.20-3.0 mg/kg) 24 and 2 h before being submitted to the forced swim, a test in which antidepressants regularly reduce immobility and exert few or no actions on locomotor activity. In order to discard the cumulative effects of progesterone and a possible effect from the repetition of the swimming test, all animals received one of several progesterone doses in a different sequence following a completely randomized experimental intrasubject design.
Results:
Ovariectomy did not modify immobility in the forced swim test as compared to control tests practiced before surgery. A dose of 0.80 mg/kg strongly reduced the total time of immobility in forced swim test (p < 0.001), but did not modify locomotor activity. In a drug-free control test applied 1 week after the last injection of progesterone, immobility returned to the higher values observed in the control tests.
Conclusions:
From these results, it is concluded that progesterone may possess some anti-depressant-like activity.
