Better Brains
How do brain cells communicate?
Brain cells communicate by passing signals (chemical messengers also called neurotransmitters) from one cell to another. Each cell has a place to receive the chemical that carries the message (receptor.) The chemical must cross a small space between each cell to be successful. In the space between the sending cell and the receiving cell specific enzymes can affect the message.
What is the role of acetylcholine in memory loss?
At the end of the nerve cell sending a message, the chemical messenger (acetylcholine) is released and ferries the message into the receptor of the receiving nerve cell. After delivering the message, acetylcholine is broken down and reabsorbed to be used again. In memory loss, less acetylcholine may be available to carry messages.
When scientists chemically blocked receptors for the neurotransmitter called acetylcholine, even healthy young people found it harder to learn and remember. The findings may also help to explain why conditions associated with decreased acetylcholine in the brain cause problems with memory function.
When does the imbalance of acetylcholine begin?
A normal decline in the nerve cells found in the brain can begin in the early forties. The aging process is a result of body cells getting older. Some lapses in the ability to remember are a normal part of aging.
How does the body compensate for this imbalance?
In early memory loss associated with a condition called mild cognitive impairment or MCI, there is actually an increase in the activity of an enzyme that makes acetylcholine.2 This is possibly the brain's way of compensating for imbalances that result from nerve cell loss. Increasing acetylcholine activity in brain cells may help the brain in its struggle to maintain the right level of this important memory neurotransmitter.
How do Alzheimer's or Dementia Medications Work?
Cholinesterase inhibitors increase levels of acetylcholine by inhibiting the enzyme that breaks it down. These medications that slow the breakdown of acetylcholine are indicated in early to middle stages of Alzheimer's. Making more acetylcholine available to brain cells may mean modest improvements in attention, memory and activities of daily living for some. This is how cholinesterase inhibitors, drugs that slow the breakdown of acetylcholine in Alzheimer's patients, help address forgetfulness.1
- Atri A, et al. Blockade of Central Cholinergic Receptors Impairs New Learning and Increases Proactive Interference in a Word-Paired-Associate Memory Task. Behavioral Neuroscience. 2004;118(1):223-236.
- DeKosky S, et al. Upregulation of Choline Acetyltransferase Activity in Hippocampus and Frontal Cortex of Elderly Subjects with Mild Cognitive Impairment. Ann Neurol. 2002;51:145-155.