Stressors can affect immobility time and response to imipramine in the rat forced swim test

• Published in: Pharmacology, biochemistry and behavior biochemistry and behavior, 2009-02, Vol.91 (4), p.542-548
• Main Authors: Gutiérrez-García, Ana G., Contreras, Carlos M.
• Format: Article
• Language: English
• Subjects: Alarm odors; Animals; Antidepressant; Antidepressive Agents, Tricyclic - pharmacology; Biological and medical sciences; Conditioning, Operant - drug effects; Dose-Response Relationship, Drug; Electroshock; Emotional stress; Emotions - physiology; Forced swim test; Imipramine; Imipramine - pharmacology; Male; Medical sciences; Motor Activity - drug effects; Neuropharmacology; Odorants; Pharmacology. Drug treatments; Physical stress; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Rats; Rats, Wistar; Stress, Psychological - psychology; Swimming - psychology
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/j.pbb.2008.09.008

We subjected Wistar rats to the forced swim test (FST) to compare the effects of two doses of imipramine in physically stressed rats (P: unavoidable electric footshocks), emotionally stressed rats (E: odors), or non-stressed rats (C). Stress or control sessions lasted 35 days. Drug treatments began on day 21 and continued for the next 14 days. E rats were placed for 10 min, once per day for 35 days, in a small non-movement-restricting cage impregnated with urine collected from a P rat. E and P rats exhibited opposite changes in locomotion. After 21 days of stress sessions, P rats displayed the longest immobility times in the FST, followed by E rats. In the P group, on day 7 of treatment (day 28 of the study), imipramine (2.5 mg/kg) reduced immobility time to baseline values. In the E group, immobility time decreased only after 14 days of treatment with the low imipramine dose. The high dose of imipramine (5.0 mg/kg) reduced immobility time at day 7 of treatment in all groups. In conclusion, physical and emotional stress similarly increased immobility time in the FST, but emotional stress appears to be more resistant to imipramine treatment.