title: Depression-related anhedonic behaviors caused by immobilization stress: a comparison with nicotine-induced depression-like behavioral alterations and effects of nicotine and/or "antidepressant" drugs.
abstract: Anhedonia, an affective symptom related to the inability to experience pleasure, is one of the representative symptoms observed in depression. In the present study, considering that repeated nicotine (NC) also causes "depressive" symptoms, the depression-related anhedonic behavioral alterations caused by a typical depression-inducing stressor, immobilization stress (IM), combined with or without NC administration, were examined in mice and compared with the depression-like behavioral alterations caused by NC. In the repeated IM (10 min, 4 days) group, as well as the repeated NC (0.3 mg/kg, s.c., 4 days) group, depression-related behavioral despair was observed in both forced swimming and tail suspension tests. Depression-related anhedonic behavioral alterations, as judged in the sucrose test, were observed only in the IM group. In the group treated with IM plus NC (IM-NC group), NC antagonized the IM-induced anhedonic attenuation of sucrose consumption in the sucrose test. Furthermore, in the IM-NC group, NC attenuated the effects of antidepressants which inhibit the reuptake of monoamines in the forced swimming test. Against the IM-induced anhedonia in the sucrose test, the cannabinoid agonists anandamide and CP 55940, in addition to the antidepressants previously reported, restored the preference for sucrose to control levels, with or without NC co-treatment. The absence of anhedonic behavioral alterations, the antidepressant-like anti-anhedonic effects against IM, and the effects against some antidepressant drugs all seemed to be characteristic of the effects of NC. Neural mechanisms other than those involved in the depression-like effects of NC seemed to contribute to the IM-induced anhedonic component of depression.
authors.affiliation: Department of Legal Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan. thayase@mri.biglobe.ne.jp
authors.forename: Tamaki
authors.initials: T
authors.lastname: Hayase
mesh_terms: D000342:Affective Symptoms / Q000139:chemically induced / Q000209:etiology*; D000818:Animals; D000928:Antidepressive Agents; D002186:Cannabinoids; D003863:Depression / Q000139:chemically induced* / Q000523:psychology*; D019417:Hindlimb Suspension; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009538:Nicotine; D012149:Restraint, Physical / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D000928:Antidepressive Agents; D002186:Cannabinoids; D009538:Nicotine