November 1, 2005
A new drug being tested to treat cancer may have memory-boosting benefits for those with Alzheimer's disease, a research study in marine snails shows. While it's a long way from sea mollusks to people, scientists are encouraged to conduct follow-up tests to better understand the brain defects that lead to Alzheimer's and to determine whether the medicine may one day have benefits for the estimated 4.5 million Americans who suffer from the memory-wasting disease.
The experimental drug, called bryostatin, stimulates brain cells to produce proteins that are critical for long-term learning and memory. Marine snails exposed to the substance performed better on navigation mazes, and the benefits lasted for weeks, researchers from the Blanchette Rockefeller Neurosciences Institute in Rockville, Maryland report.
In earlier lab experiments in rats and mice, the researchers found that the drug reduces levels of beta-amyloid, a toxic substance that builds up in the brains of those with Alzheimer's disease. In animals, it also enhanced learning and memory retention. "Now we've taken this drug and explored in great detail how it may affect memory itself," said study leader Dr. Daniel Alkon.
The researchers studied marine mollusks from the genus Hermissenda, a snail-like creature long used by scientists who study learning and memory. When bryostatin was added to the sea snail's watery environment, it greatly boosted their ability to respond to a light stimulus. Normally, these animals remember such training for about seven minutes, but with bryostatin, their retention lasted for over a week. In another experiment, the researchers found that exposure to the drug increased protein production by mammal brain cells by up to 60 percent. The investigators speculate that the drug may aid in the production of proteins that consolidate short-term memories into long-lasting ones.
Bryostatin is one of dozens of new drugs that are now being suggested for testing against Alzheimer's disease. Researchers hope that continued animal research may open up new avenues of exploration and potential new treatments for Alzheimer's disease in people. Basic laboratory research is critical for one day finding new and effective treatments against Alzheimer's disease. The Fisher Center for Alzheimer's Research Foundation is leading the way in the search for a cure. To learn more and to receive regular news updates, visit www.ALZinfo.org.
Daniel L. Alkon, et al: Proceedings of the National Academy of Sciences, Oct. 25, 2005.