Experimental drug targets Alzheimer's.

A novel drug reverses some Alzheimer's-type symptoms in mice, a study shows.

Researchers used mice genetically engineered to accumulate waxy plaques of beta-amyloid protein in their brains, a symptom of Alzheimer's disease in people. Then, over 8 weeks, the scientists regularly injected some mice with the new drug and gave others inert shots.

The researchers tested how well the mice learned and recalled how to navigate a water maze. Mice treated with the experimental drug, called AF267B, did better than the mice getting inert shots, the researchers report in the March 2 Neuron.

A test to gauge "emotional memory" yielded less-promising results. Mice were given a mild shock from the floor when they entered an otherwise-inviting cage chamber. Normal mice subsequently recalled this disturbing experience and avoided the chamber, but the Alzheimer's mice didn't, even after getting AF267B.

The water-maze results suggest that the drug benefits the brain's cerebral cortex and the hippocampus, areas that handle spatial learning and recall and that are affected in Alzheimer's disease, says study coauthor Frank M. LaFerla, a neuroscientist at the University of California, Irvine. Results of the floor-shock test suggest that the amygdala, an Alzheimer's-affected brain area that's associated with emotional memory, didn't benefit from the drug, says LaFerla.

The team further reports that in the Alzheimer's mice, the drug reduced beta-amyloid plaques in the hippocampus but not in the amygdala. The drug, called NGX267 by its maker TorreyPines Therapeutics in San Diego, is now undergoing preliminary tests in people.--N.S.