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Cannabinoids promote and produce anxiolytic- and antidepressant-like effects

The hippocampal dentate gyrus in the adult mammalian brain contains neural stem/progenitor cells (NS/PCs) capable of generating new neurons, i.e., neurogenesis.

American Society for Clinical Investigation 14 10 2005

Most drugs of abuse examined to date decrease adult hippocampal neurogenesis, but the effects of cannabis (marijuana or cannabinoids) on hippocampal neurogenesis remain unknown. This study aimed at investigating the potential regulatory capacity of the potent synthetic cannabinoid HU210 on hippocampal neurogenesis and its possible correlation with behavioral change. We show that both embryonic and adult rat hippocampal NS/PCs are immunoreactive for CB1 cannabinoid receptors, indicating that cannabinoids could act on CB1 receptors to regulate neurogenesis. This hypothesis is supported by further findings that HU210 promotes proliferation, but not differentiation, of cultured embryonic hippocampal NS/PCs likely via a sequential activation of CB1 receptors, Gi/o proteins, and ERK signaling. Chronic, but not acute, HU210 treatment promoted neurogenesis in the hippocampal dentate gyrus of adult rats and exerted anxiolytic- and antidepressant-like effects. X-irradiation of the hippocampus blocked both the neurogenic and behavioral effects of chronic HU210 treatment, suggesting that chronic HU210 treatment produces anxiolytic- and antidepressant-like effects likely via promotion of hippocampal neurogenesis.

Wen Jiang 1,2, Yun Zhang 1, Lan Xiao 1, Jamie Van Cleemput 1, Shao-Ping Ji 1, Guang Bai 3 and Xia Zhang 1

1Neuropsychiatry Research Unit, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.

2Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi’an, People’s Republic of China.

3Department of Biomedical Sciences, Dental School, Program in Neuroscience, University of Maryland, Baltimore, Maryland, USA.

Address correspondence to: Xia Zhang, Neuropsychiatry Research Unit, 103 Wiggins Road, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E4. Phone: (306) 966-2288; Fax: (306) 966-8830; E-mail: zhangxia at duke.usask.ca.

Update Thursday 3 November 2005 11:57, published Wednesday 2 November 2005 18:45