WASHINGTON _ Like an aging track star, the older brain justdoesn't work as fast as it did when it was young. For reasons not fullyunderstood, older people don't create memories at the same rate asyoung people. Or in the time-honored tradition of the cliche: youcan't teach an old dog new tricks.
However, preliminary studies of a drug called Ampalex presentedSunday by University of California Irvine neuroscientist Gary Lynchat the 26th annual meeting of the Society for Neuroscience couldhave that old dog barking up a new tree as potentially offering a newtherapy for Alzheimer's disease.
These results were so encouraging that Cortex Pharmaceuticals Inc.,of Irvine, Calif., which has licensed the rights to the drug from theUniversity of California, entered into a cooperative research anddevelopment agreement with the National Institutes of Health onFriday to test the drug's memory enhancement abilities in 16Alzheimer's patients. Those studies will begin early next year.
"Here is a small molecule that works on the excitatory nervecommunication that naturally declines as we age," Lynch said.
Ampalex, or CX-156, belongs to a class of drugs known asampakines. These drugs enhance the response of the AMPAreceptors on neurons which transmit the signals between neurons thatare vital for learning and memory. Preclinical studies of ampakinesshowed that rats who received the drug could remember mazes longerthan untreated rats. When tested on middle age rats who havesignificantly diminished ability to remember mazes, the drug allowedthe rats to perform as well as the young rats.
The studies presented Sunday showed similar results in humans. Theresearchers studied 16 male medical students in Sweden and hadthem look at a collection of photographs from various magazines andthen asked the students to try to remember who the photographer foreach one was. The researchers tested them at 10 minutes and 24hours later. Those who had taken the drug made more correctphotography associations after 24 hours than those who received theplacebo.
In a test of remembering nonsense syllables, such as nib, groll andorp, the young men who received the ampakine remembered more ofthe syllables than those who were on placebo.
The researchers also tested the drug in 30 older men in Berlin,Germany. The researchers examined the ability of the men aged 65 to76 to remember nonsense syllables. The six men who received thehighest dose of the drug doubled their scores.
"The most dramatic aspect about this study is that the scores of themen on the highest dose of the drug performed like the young men,"Lynch said. "We see the most benefit in those with the worst deficit."
While the results are exciting, Donald Price from the Johns HopkinsSchool of Medicine, in Baltimore, noted that "these are still verypreliminary studies that need to be confirmed."
Lynch noted that the only noticeable side effect of the drug was anurge to swallow that several patients on the higher doses experienced.
Because the drug so dramatically increases the activity of neurons inthe neocortex, Lynch speculated that it may have added benefitsbeyond the few minutes that it is actively in the bloodstream. "Thismay be a use it or lose it phenomena," said Lynch. "Stimulating theAMPA receptors may produce [substances that maintain the integrityof neurons]." n
-- Lisa Seachrist Washington Editor
(c) 1997 American Health Consultants. All rights reserved.