Pubdate: Fri, 06 Oct 2006
Source: Australian, The (Australia)
Copyright: 2006sThe Australian
Author: Leigh Dayton, Science writer


IT seems illogical, but the same compound that addles the brains of 
marijuana users may help treat the symptoms and slow the onset of 
Alzheimer's disease, the leading cause of dementia among elderly 
people. In laboratory experiments, the compound, 
delta-9-tetrahydrocannabinol (THC), preserved levels of a brain 
chemical that declines in Alzheimer's, permitting the build-up of 
brain-gumming "amyloid plaques".

The plaques are the hallmark of Alzheimer's and its dementia-inducing damage.

"Our results provide a mechanism whereby the THC molecule can 
directly impact Alzheimer's disease pathology," researchers reported 
in the US journal Molecular Pharmaceutics.

The team - led by organic chemist Kim Janda of the Scripps Research 
Institute in La Jolla, California - claimed that THC holds real 
promise as a "drug lead", a model for developing new and more 
effective treatments for Alzheimer's.

Existing drugs such as donepezil, sold as Aricept in Australia, 
inhibited an enzyme called acetylcholinesterase which broke down 
acetylcholine, the brain chemical that prevents formation of amyloid plaques.

But THC not only acted against the enzyme, it also targeted plaque formation.

According to pathologist and Alzheimer's expert Colin Masters, the 
findings were novel and unsuspected.

"It might be possible to reformulate or rebuild the THC molecule so 
it has the anti-Alzheimer's effects without causing disturbances of 
cognition - getting high or stoned," said Professor Masters, from the 
University of Melbourne and the Mental Health Research Institute.

That's so because THC acts on one group of brain molecules when it 
triggers a buzz and another when it fights brain-clogging plaques.
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