Molecular PharmaceuticsScientists are reporting discovery in laboratory
experiments of a previously unknown molecular mechanism in which the
active ingredient in marijuana may slow the progression of Alzheimer's
disease (AD). Scripps Research Institute's Kim D.
Janda and colleagues used laboratory experiments to show that
delta-9-tetrahydrocannabinol (THC) preserves brain levels of the key
neurotransmitter acetylcholine.

Existing medications for AD, including donepezil and tacrine, also
relieve ADsymptoms by inhibiting the enzyme, acetylcholinesterase,
which breaks downacetylcholine. THC does so by inhibiting an
alternative site onacetylchlolinesterase and at lower concentrations,
Janda's group reports in anarticle in the current (Oct. 2) issue of the
ACS bimonthly journal, Molecular
Pharmaceutics. Their experiments show that THC also prevents formation
of theamyloid plaques that are a hallmark of AD and its damage to the
brain.