Epilepsy is a condition that causes sudden seizures in patients, affecting about 1% of the population. The seizures involve excessive and repetitive firing of neurons in the brain, and the cause of this phenomenon has long puzzled scientists. Now, using fluorescence calcium sensors, researchers have observed the role of astrocytes in epileptic seizures. They have discovered that astrocyte activity begins approximately 20 seconds before the onset of excessive neuronal firing in epilepsy.
Researchers at Tohoku University have used fluorescence calcium sensors to track astrocyte activity, and they have found that astrocyte activity begins about 20 seconds before the start of epileptic neuronal hyperactivity. This discovery suggests that astrocytes may have a significant role in triggering epileptic seizures by promoting hyperactivity in the neural circuit.
The findings were published in the journal Glia on April 9, 2024.
Astrocytes are non-neuronal glial cells that make up nearly half of the brain. Studies have shown that they regulate the local ionic and metabotropic environment in theThe brain has largely overlooked the role of astrocytes in brain function because they do not show easily monitored electrical activity. However, fluorescence sensor proteins are changing this by revealing more about the fascinating activity of astrocytes.
Professor Ko Matsui, who led the research at Tohoku University’s Super-network Brain Physiology lab, stated that astrocytes appear to play a crucial role in controlling neuronal activity and synaptic plasticity in both normal and abnormal situations. Therefore, astrocytes could be a potential new target for treating epilepsy.
When brain tissue comes in contact with metals like copper, it can cause inflammation that leads to frequent seizures in mice. Matsui and his team witnessed these seizures and found that astrocyte activity may be the cause of the increased neuronal activity. Additionally, low-intensity direct current stimulation can activate astrocytes. The researchers observed that this stimulation caused a significant rise in astrocyte calcium levels, followed by a seizure-like increase in neuronal activity. Blocking the metabolic activity of the astrocytes with fluorocit prevented this reaction.The epileptic neuronal hyperactivity was significantly reduced, indicating that astrocytes have the potential to regulate neuronal activity. Lead study investigator Shun Araki suggests that with proper guidance, astrocytes’ functions could be utilized to address various neurological conditions, including epilepsy and potentially improving cognitive abilities beyond natural limitations.
