The co-relationship between immobility as a depressive model and learning in the forced mouse swimming test

• Published in: Japanese Journal of Pharmacology Vol. 64; no. suppl.2; p. 360
• Main Authors: Tadano, Takeshi, Arai, Yuichiro, Kinemuchi, Hiroyasu, Kisara, Kensuke
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Pharmacological Society 1994
• ISSN: 0021-5198
• DOI: 10.1016/S0021-5198(19)51074-5

The forced swimming test developed by Porsolt et al. has been widely used as a suitable method for screening of antidepressants. In the present study, we attempted to clarify how the animal immobility induced in this test is adapted to the clinical phenomena of human depression. In addition, another attempt was also performed to clarify whether the longer immobility time found at the second swimming trial simply resulted from a learning effect by floating in the water. For these, 5 different strains of mice, ddY BALB, ICR, C57BL and C3H, were used for examining a possible genetic factor(s), which may primarily contribute to easiness in occurrence of such immobility. Only C3H mice showed a reduced rate of immobility. An electric shock given, as a stressor, to C57BL and ddY mice induced a markedly suppressed locomotion with the prolonged immobility rate, but failed to induce any change in C3H mice. In ddY mice, scopolamine (2.5 mg/kg, i.p.) or cycloheximide (150 mg/kg x 3, i.p.) induced amnesic effects, as judged by the passive avoidance response, but immobility was not affected by these drugs. These results clearly indicate that mouse immobility is partially adapted to depression in view of the behavioral despair state rather than the learning effect obtained after the first forced swimming trial.