Monday, April 26, 2010
An American study has shed new light on the mechanism behind epilepsy attacks in the brain. Epilepsy attacks, which can manifest as fits in some people, or "absences" in others, are caused by too much electrical signaling from the brain's neurons.In epilepsy, excessive signaling between neurons, a major type of brain cell that communicates electrical signals across gaps called synapses, can lead to epileptic seizures. However, another class of brain cells called glia can regulate those signals. Among the glia are star-shaped cells called astrocytes-the particular focus of the research.
The astrocytes is known to have a wide range of functions, including supplying nutrients to other brain cells, and even helping the brain cope with damaged nerve cells and it is key to brain dysfunction and opens the potential for novel therapeutic strategies in epilepsy. The researchers focused on an abnormal condition called reactive astrocytosis, known to occur in many neurological diseases. The astrocytes swell to a large size and change expression levels of a number of proteins. The impact of reactive astrocytosis on brain function is difficult to investigate because it usually occurs in the context of brain inflammation and abnormal changes in surrounding cells.
In epilepsy, inhibition is not working properly, and uncontrolled signaling leads to epileptic seizures. Because both disrupted inhibition and reactive astrocytosis are known to occur in other neurologic conditions, including many psychiatric disorders, traumatic brain injury, and neurodegenerative disorders such as Parkinson's disease, our findings may have wide implications.
The researchers solved this problem by using a virus to selectively cause reactive astrocytosis without triggering broader inflammation and brain injury, in a mouse model. They were able to focus on how the altered astrocytes affected specific synapses in neurons in the brain's hippocampus.
posted by emedinfo
@10:44 PM
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