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Nicotine could in future yield a new treatment
for Alzheimer's disease, scientists have revealed.
Researchers found that a by-product of the
compound which hooks smokers appears to protect the brain from the
devastating dementia illness.
But the discovery should not be seen as an excuse
to smoke. The substance, nornicotine, is toxic, and could not itself
be used as a medication. But scientists believe further research
might produce harmless compounds that mimic the action of
nornicotine in fighting Alzheimer's.
Previous studies already suggested that cigarette
smoking may delay the onset of Alzheimer's, but no-one was sure
how.
There have been a number of different theories,
such as stimulation of deficient molecular "receptors" that bind on
to nicotine.
The new research indicates that nornicotine,
produced when nicotine is broken down in the body, prevents the
formation of protein lumps, or plaques, in the brain associated with
Alzheimer's.
Plaque formation was reduced when two US
scientists incubated nornicotine and glucose with the amyloid beta
proteins from which the deposits are made. Nornicotine is involved
in a reaction between sugars and proteins called glycation, which is
normally considered harmful.
The findings were published today in the journal
Proceedings of the National Academy of Sciences.
Tobin Dickerson and Kim Janda, from The Scripps
Research Institute, la Jolla, California, wrote: "Nicotine and
nonicotine treatments are intriguing and potentially valuable
treatments for AD (Alzheimer's disease). However, both compounds
have significant toxicity and known psychoactivity. These results
argue for increased study into new therapeutic compounds capable
of..modifying A beta while displaying reduced toxicity and
psychoactivity."
They added that nornicotine may play a role in
the formation of amyloid plaques in other diseases, such as
Parkinson's. | 
