The posting below is from another newsgroup which I frequent.   The man is
actually a retired rocket scientist and he usually gets very good
information.

I told him that if nicotine did any good, then smokers wouldn't get it, and
we all know of smokers who have.

He replied;

Of course. The cigarette delivery system for nicotine
is very, very bad. Here's the abstract of a very recent
article on nicotine and Alzheimer's. Notice the last
sentence. You can get the full article from PubMed
by means of the PMID number.

George W. Cherry

Reduced levels of Abeta 40 and Abeta 42 in brains of smoking controls and
Alzheimer's patients.

Hellstrom-Lindahl E, Mousavi M, Ravid R, Nordberg A.

Department of Neurotec, Division of Molecular Neuropharmacology, Karolinska
Institutet, Huddinge University Hospital, Stockholm, Sweden.
Ewa.Hellstom-Lindahl@neurotec.ki.se

The effects of nicotine on levels of Abeta 40 and Abeta 42 and nicotinic
receptor binding sites were studied in brains from nonsmoking and smoking
patients with Alzheimer's disease (AD) and aged-matched controls. The levels
of soluble and insoluble Abeta 40 and Abeta 42 in frontal cortex and Abeta
40 in temporal cortex and hippocampus were significantly decreased in
smoking AD patients compared to nonsmokers with AD. In smoking controls the
levels of soluble and insoluble Abeta 40 and Abeta 42 in the frontal and
temporal cortex were significantly lower than in nonsmoking controls. The
binding of [(3)H]cytisine in temporal cortex was significantly increased in
smokers with AD compared to nonsmokers with AD. In smoking controls
[(3)H]cytisine and [(3)H]epibatidine binding were significantly increased
from 1.5- to 2-fold compared to nonsmoking controls whereas binding sites
for [(125)I]alpha-bungarotoxin was less up-regulated. These results indicate
that selective nicotinic receptor agonists may be a novel protective therapy
in AD by reducing Abeta levels as well as the loss of nicotinic receptors in
AD brain.

PMID: 15006705 [PubMed]