How Alzheimer’s Medicines Help

(Ivanhoe Newswire) -- New research shows how the only government-approved treatments for mild-to-moderate Alzheimer’s disease work to improve symptoms.

The new finding may shed light on how cholinesterase inhibitors help alleviate dementia symptoms. When scientists chemically blocked receptors for an important neurotransmitter called acetylcholine, healthy young people found it significantly harder to learn and remember. Cholinesterase inhibitors boost acetylcholine by reducing the enzyme that breaks it down. Understanding their effects on major symptoms during disease progression may help scientists develop more targeted and effective drugs, as well as avoid medications that may be harmful to memory function.

At Massachusetts General Hospital in Boston, researchers injected 12 of 28 young healthy adults with scopolamine, an “anti-cholinergic” drug. Investigators then measured how well participants learned new pairs of words, a common memory test. Two other groups of eight participants were tested but were either given no drugs or the medicine glycopyrrolate to mimic the dry mouth produced when scopolamine is given.

As expected, memory for word pairs learned after taking scopolamine suffered significantly but word pairs learned immediately before injection were spared. The study suggests anti-cholinergics may serve as a kind of cognitive “stress test” for elderly patients who have underlying dementia in its earliest stages. This would unmask symptoms hard to detect otherwise.

However, researchers caution the chronic use of anti-cholinergic medications by elderly people would be highly discouraged, especially if they are cognitively impaired. These drugs, if used particularly during waking hours, are expected to interfere with acquisition and future recall of new and related memories.

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SOURCE: Behavioral Neuroscience, 2004;118:223-226