Study carried out by Professor. Maiken Nedergaard and his Colleagues at the University of Rochester Medical center, Newyork has found that Astrocytes has been found to be involved in the initiation and propogation of epileptic discharges , which was published in Nature Medicine.
Epilepsy occurs when the brain chemical, glutamate, stimulates neurons to act in an uncontrolable way leading to seizures or loss of consciousness. Most of the research has been focussed on the brain cells and not in the neurons and this new study will open new avenuses for the pharmacological treatment of epilepsy. Neurologists generally believe that epilepsy causes the production of abnormal cells called reactive astrocytes - oversized, bloated, star-shaped cells that no longer function properly in their "housekeeping" role of maintaining the brain's optimum chemical environment.
AdvertisementAstrocytes are a major type of brain cell, but because they are not involved in electrical activity within the brain, they have been studied relatively little. The cell type is found in larger proportion - and with more "points" on the star-shaped cell - in animals with higher brain function. Monkeys have roughly the same number of astrocytes as neurons in their brains, whereas humans have 10 times as many astrocytes as neurons. Recently, more has been discovered about the importance of these cells and the role they play in diseases, from stroke to Alzheimer's.
Donald Weave, president of Epilepsy Canada, agrees. The role of glial cells, the cells that surround and support neurons, in epilepsy and neurology "has been understudied", he says. "We have been hammering away at the same old approaches for years and so a new way in with astrocyte involvement would be very useful."
Professor Nedergaard said, "To our great surprise, we found that there was an increase in reactive astrocytes in all five models, which could not have been caused by over-firing of the neurons as expected - because there had been no neural firing," "And the reactive astrocytes were producing excessive glutamate in the rats. It turns out that reactive astrocytes trigger epilepsy, and not the other way around."
Source: The New Scientist