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 The study has also shown that the brain changes - and improved performance - remain after the drug is withdrawn.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.
