ACM-Bulletin of 16 October 2005
-------------------------------------------------------

* Science: Cannabinoids may promote the development of new brain cells
* Science: Mice without CB1 receptors show accelerated cognitive impairment
* Australia: Survey on cannabis for medical purposes

1.

Science: Cannabinoids may promote the development of new brain cells

According to animal research at the University of Saskatchewan, Canada, cannabinoids that bind to the CB1 receptor promote the development of new nerve cells in the hippocampus, a brain region that is very important for memory and behaviour. This cannabinoid effect may decrease anxiety and depression.

Scientists used the synthetic cannabinoid HU210 that acts similar to THC on CB1 receptors in the brain. Chronic, but not acute treatment with this cannabinoid promoted nerve cell proliferation in the hippocampus of adult rats and exerted anxiolytic- and antidepressant-like effects.

Other illegal and legal drugs, including opiates, alcohol, nicotine and cocaine, have been shown to suppress the formation of new brain cells when used chronically, but the effect of cannabis on that process was uncertain. Cannabis appears "to be the only illicit drug whose capacity to produce increased ... neurons is positively correlated with its (anti-anxiety) and anti-depressant- like effects," Dr. Xia Zhang and his colleagues wrote in an article for the November issue of the Journal of Clinical Investigation, which was already posted online on 13 October.

(Sources: Jiang W, Zhang Y, Xiao L, Van Cleemput J, Ji SP, Bai G, Zhang X. Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects. J Clin Invest. 2005 Oct 13 [Electronic publication ahead of print]; United Press International of 13 October 2005)

2.

Science: Mice without CB1 receptors show accelerated cognitive impairment

Researchers of the University of Bonn demonstrated that young mice (6-7 weeks) with a genetic deletion of the cannabinoid-1 receptor performed as well as normal mice, or often better, in a number of learning and memory tasks. In contrast, the performance of older mice (3-5 months) lacking CB1 receptors was much worse than that those of the normal animals with the same age. In most tests, these mice performed at the same level as old animals (14-17 months), suggesting that the age-related decline in cognitive performance is accelerated in the absence of
CB1 receptors. This rapid decline in CB1-deficient animals was accompanied by a loss of nerve cells in the hippocampus.

"Our results suggest that the abscence of CB1 receptors results in an accelerated decrease of cognitive functions," lead researcher Dr. Andreas Zimmer said. He noted that these results may have consequences for the medical use of CB1 receptor antagonists if used long-term.

(Sources: Bilkei-Gorzo A, Racz I, Valverde O, Otto M, Michel K, Sarstre M, Zimmer A. Early age-related cognitive impairment in mice lacking cannabinoid CB1 receptors. Proc Natl Acad Sci U S A 2005 Oct 12; [Electronic publication ahead of print]; www.innovations-report.de of 12 October 2005; www.heise.de of 15 October 2005)

(More at the IACM-Bulletin archives: http://www.cannabis- med.org/)

International Association for Cannabis as Medicine (IACM) Rueckertstrasse 4
D-53819 Neunkirchen
Germany
Phone: 2247-968083
Fax: 2247-9159223
Email: info@cannabis-med.org
http://www.cannabis-med.org

URL: http://www.umsl.edu/~keelr/pot_health.htm
Owner: Robert O. Keel: rok@umsl.edu
Last Updated: Tuesday, October 31, 2006 2:37 PM