Sub-chronic administration of rimonabant causes loss of antidepressive activity and decreases doublecortin immunoreactivity in the mouse hippocampus.
Rimonabant is a cannabinoid receptor 1 antagonist, and is used to treat anorexia and obesity. However, it has been suggested that rimonabant may act as a depressant. In the present study, we investigated the depressive effects of rimonabant using behavioral and biochemical methods. A single treatment with rimonabant (10mg/kg, p.o.) reduced immobility duration in the forced swimming test (FST) to a level similar to that observed for the tricyclic antidepressant, imipramine (15mg/kg, i.p.). However, mice treated with rimonabant for 2 weeks did not show any significant reductions in immobility duration versus vehicle-treated controls. To investigate why the antidepressant effect of rimonabant disappeared after extended treatment, we carried out 5-bromo-2-deoxyuridine (BrdU) and doublecortin (DCX) immunohistochemistry assay. Numbers of BrdU-immunoreactive cells were not significantly changed after administering rimonabant (10mg/kg, p.o.) for 2 weeks in the hippocampal dentate gyrus (DG), but interestingly, numbers of DCX-immunopositive cells in the DG were significantly reduced after 2 weeks of rimonabant treatment at doses of 1 or 10mg/(kgday) compared with vehicle-treated controls (P<0.05). These results suggest that sub-chronic treatments with rimonabant inhibit cell proliferation in DG, and that a lack of antidepressive activity may be related to a reduction in cell proliferation in this region.
Lee
Seungjoo
S
Department of Life and Nanopharmaceutical Sciences, College of Pharmacy, Kyung Hee University, Hoeki-dong, Dongdaemoon-Ku, Seoul 130-701, Republic of Korea.
Kim
Dong Hyun
DH
Yoon
Sung-Hwa
SH
Ryu
Jong Hoon
JH
D000818:Animals; D019440:Anti-Obesity Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001522:Behavior, Animal / Q000187:drug effects; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D003863:Depression / Q000139:chemically induced* / Q000503:physiopathology; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D055495:Neurogenesis / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009479:Neuropeptides / Q000378:metabolism*; D010880:Piperidines / Q000008:administration & dosage / Q000009:adverse effects*; D011720:Pyrazoles / Q000008:administration & dosage / Q000009:adverse effects*; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors*; D000077285:Rimonabant; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology
D019440:Anti-Obesity Agents; C000714847:Dcx protein, mouse; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D001973:Bromodeoxyuridine; D000077285:Rimonabant