Researchers at the University of California, Irvine have discovered that a decrease in the level of dopamine produced by the brain causes accelerated memory decline in Alzheimer's patients.
The research team focused on the entorhinal cortex, a brain region responsible for forming memories and transmitting information to the hippocampus. Experiments showed that the level of dopamine in this region drops to less than 20% of the normal rate in Alzheimer's patients, which weakens the ability of nerve cells to respond to signals that should be stored as memories.
To test whether this decline could be reversed, the researchers artificially increased dopamine levels, which restored the ability to form memories. A similar effect was observed with the drug levodopa, currently used to treat Parkinson's disease.
Scientists have noted that the primary focus in treating Alzheimer's disease has previously been on removing toxic proteins such as amyloid and tau from the body, but recent research suggests that disrupting dopamine-related neural circuits may be a crucial factor in treating this disease.
Researchers believe that targeting the dopamine system could represent a new therapeutic approach for Parkinson's disease, particularly in its early stages, when symptoms of memory impairment begin to appear.
