DRUG IS FOUND TO IMPROVE MEMORY OF RATS

Researchers testing a so-called "smart drug" in animal trials at NUI Dublin
have noted a remarkable improvement in both memory and problem-solving in
rats receiving the substance.

If approved for human use, the drug could have an impact on a number of
human illnesses, including schizophrenia and Alzheimer's disease, and in
improving memory generally, according to Prof Ciaran Regan of the
department of pharmacology at NUI Dublin.

How the drug actually improved memory and learning ability remained a
mystery, however, he said. "While [the drugs] are very clean, with no
apparent side-effects, their action is not known."

The drug was produced by a Japanese pharmaceutical company but has not yet
been put forward for consideration in human trials, he explained. There was
a great deal of international research aimed at finding smart drugs and
memory-enhancing pharmaceuticals, in particular for the treatment of
Alzheimer's disease. One, tacrine, is already approved for human use.

The work at NUI Dublin is part of a comprehensive study of how environment
can affect the mental capacity of rats. It has already been established
that rats kept in an "enriched" environment have improved memory and
learning skills compared with those kept in a less stimulating
"impoverished" environment.

The enriched enclosure is built on several levels which can be changed to
offer variety. Toys are available to these rats and they can acquire hidden
food if they overcome challenges. The impoverished enclosure does not offer
this level of stimulation.

The NUI Dublin study found that the enriched conditions encouraged the
growth of specific brain cells associated with the hippocampus, a small
area in the temporal lobe.

"This is known to be an area critical for memory. It is involved in storing
information transiently," Prof Regan said. "You get very dramatic
differences in the structures of the brain comparing the enriched with the
impoverished environments."

The drug under study, however, brings about the same kind of changes in the
rat's brain even without the enriched conditions. The study has also shown
that the brain changes - and improved performance - remain after the drug
is withdrawn.

Such a drug, if it worked, would have significant implications in a human
context, Prof Regan believes. The part of the brain affected by the drug is
known to be underdeveloped in schizophrenics. The drug could be
administered to children known to have this condition as a way to enhance
brain-cell growth.

It could also have an impact on treatment of Alzheimer's patients. The
neural pathways leading to and from the hippocampus are severely damaged in
Alz heimer's patients.

Because the hippocampus is necessary for making and storing memories, this
damage is thought to be the major cause of memory impairment in these
patients. Any drug that could repair this damage would be valuable indeed.