Epilepsy Seizures: Role of Astrocytes in Neural Hyperactivity

By Nithya Somarapu on April 22, 2024

Roughly 1% of people experience epilepsy seizures, a condition in which individuals have sudden seizures. It is yet unclear what causes the repeated and excessive neuronal activation that characterizes these seizures.

Using fluorescent calcium sensors, Tohoku University researchers have now tracked astrocyte activity and found that it begins about 20 seconds prior to the commencement of epileptic neuronal hyperactivity. This implies that astrocytes have a major role in inducing epileptic seizures by promoting the neuronal circuit’s hyperdrive.

On April 9, 2024, these results were published in full in the journal Glia.

Nearly half of the brain is made up of non-neuronal glial cells called astrocytes. It has been demonstrated that they regulate the metabotropic and ionic conditions locally. However, due to their lack of readily observable electrical activity, their significance in brain function has been generally overlooked. This is being altered by fluorescent sensor proteins, which provide additional insight into the fascinating activity of astrocytes.

For more discussions on the latest advancements in neurology, you can check out the Global Neurology Summit 2024.

“Astrocytes appear to have a determinant role in controlling the state of neuronal activity and synaptic plasticity both in physiological and pathophysiological situations,” said the study’s principal investigator, Professor Ko Matsui of Tohoku University’s Super-network Brain Physiology lab. “Therefore, astrocytes could be considered as a new therapeutic target for epilepsy treatment.”

It is well known that exposure to metals like copper causes inflammation in the brain tissue, which in turn causes acute symptomatic seizures that happen a few times a day in mice. After seeing these occurrences, Matsui and his colleagues concluded that astrocyte activity might be the cause of neuronal hyperactivity in epilepsy seizures. Direct current stimulation with a modest amplitude can also activate astrocytes.

The astrocyte calcium increased significantly in response to this stimulation, the researchers observed, and this was followed by an epileptic neuronal hyperactivity episode. The amount of epileptic neuronal excitability was greatly decreased when fluorocitrate was applied to the astrocytes to limit their metabolic activity. All of these suggest that astrocytes may be able to regulate neural activity.

Shun Araki, the study’s lead scientist, emphasized that astrocytes’ abilities could be used to treat a variety of neurological disorders with the right direction. This covers epilepsy as well as the possibility of improving cognitive capacities over and above their inherent constraints.

For more information: Astrocyte switch to the hyperactive mode, Glia, DOI: 10.1002/glia.24537