Could this chemical help explain anxiety?
A recent study on anxiety examined the role of glutamate, which is a neurotransmitter. The findings could help scientists develop more effective interventions.
Almost everybody experiences anxiety in one of its forms.
Over time, evolution honed anxiety as a survival mechanism; it forms part of our "fight-or-flight" response.
The heart pumps a little faster, and there might be a sensation of nausea as the body prepares for action.
Although anxiety is a natural response, it can spiral out of control for some people.
Rather than being a protective force that helps us navigate everyday life, it becomes a burden that impacts well-being. Also, being more prone to anxiety increases the risk of developing an anxiety disorder and depression.
Beyond mental health, anxiety might also have physical effects; the authors of the new study write that sustained high levels of anxiety "may increase the risk of developing cardiovascular disease."
The Anxiety and Depression Association of America say that anxiety disorders impact almost 1 in 5 adults in the United States each year.
Anxiety disorders are as common as depression, but until relatively recently, they received much less attention.
Because of its growing prevalence, the neurological mechanisms that are involved are receiving increased attention. The latest study, which now appears in The Journal of Neuroscience, investigates the role of glutamate in the hippocampus.
What is glutamate?
Glutamate is an amino acid and the primary excitatory neurotransmitter in the brain. In recent years, studies have hinted that glutamate might be involved in anxiety.
Reductions in glutamate activity seem to increase anxious behavior, and glutamate levels within the hippocampus — which is the part of the brain primarily involved in regulating emotions and memory — seem particularly important.
Earlier studies have also concluded that two other regions of the brain work with the hippocampus to modulate anxiety; called area 25 and area 32, these regions form part of the prefrontal cortex.
However, our understanding of glutamate's role in anxiety is not fully formed — other studies have produced conflicting results.
As an example, a study using nonanxious rats found that a reduction of activity at some glutamate receptor subtypes in the hippocampus actually reduced levels of anxiety.
The authors of the latest study wanted to examine the role of glutamate in anxiety in more detail. To get a clearer picture, they ran a series of experiments on marmosets.
