Tuesday 16 January 2018 11:03am
In order to understand the injured or diseased brain we must first understand the healthy brain. This is an enormous job but it becomes even more complex when we take ageing into account. We expect our body and brain to change as we age, but what does normal brain ageing look like? How do we tell healthy from unhealthy? In order to learn about, and try to treat, illnesses like Alzheimer’s disease we need to be able to tell how far an affected person’s brain is from the rest of their age group.
The brain communicates using chemicals called neurotransmitters. These chemicals are released by your brain cells in order to send specific kinds of messages to other cells nearby. A single cell can have multiple neurotransmitters within it, all waiting to be released and trigger a signal in another cell.
Depending on the area of your brain and the purpose of the cell the neurotransmitters in that cell will be different, or will be present in different proportions. One cell could have a 1:1 ratio of all its neurotransmitters, while another could heavily favour one neurotransmitter over all the others. This kind of variety is normal for cells that have differing purposes, but new research shows that normal ageing also changes neurotransmitter ratios. This means that in order to tell if a cell had the right kinds and amounts of neurotransmitters you’d have to take into account the area of the brain, the purpose of the cell, and the age of the individual.
The specific neurotransmitters examined by BHRC researchers were glutamate and agmatine, both of which excite brain cells when released. When the researchers compared the brains of young and old animals they found that the ratios of glutamate and agmatine were significantly different. In the younger animals agmatine and glutamate co-existed in cells, however in the aged animals there was significantly less glutamate in cells with agmatine.
It’s unclear why this happens or even what the functional effects would be, however it is an important part of the ageing puzzle. Different brain chemistry may cause a different response to treatments and medications, so the more we know about how age affects the brain the better equipped we are to provide effective treatments.
The research mentioned in this article was conducted by Dr Rena Jing, Associate Professor Beulah Leitch, and Associate Professor Ping Liu. The work was made possible by funding from the Neurological Foundation of New Zealand.