The study may open the way to the treatment of various forms of acquired epilepsy and convulsions, which result from brain lesions caused by trauma, infection or tumors in the brain.
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In 1893, scientists knew about the mysterious structures called perineuronal nets wrapped around the neurons, but the function of these networks remains unknown. However, a group of scientists from the University of Virginia, headed by Harald Sontheimer (Harald Sontheimer) has identified that these networks modulate the electrical impulses in the brain. Moreover, they found that seizures may occur in the event of dissolution of networks. The results are published in the journal Nature Communications.
Initially, the researchers made this discovery in mice suffering from epilepsy, caused by a deadly brain cancer — glioblastoma, the first symptom which often become seizures. Glioblastoma is the only type of cancer whose growth is limited by space. Because the skull blocks the cancer from expanding outward, the tumor produces stimulating chemical neurotransmitter (glutamate) in an excess amount, which kills adjacent healthy cells to free up space for growth.
In addition to glutamate, the tumor secretes an enzyme that aimed at the destruction of the surrounding extracellular matrix is a gel — like substance that holds the cells of the brain on the spot. Glioblastoma, a very malignant and are known for their ability to spread in the body. The secreted enzyme is a kind of knife that cuts the cancer cells, allowing them to move freely.
To their surprise, the scientists also observed, as the enzyme attacks the perineuronal network wrapped around inhibitory GABA neurons (Gamma-aminobutyric acid) that help prevent attacks.
The Italian neuroscientist Camillo Golgi (Camillo Golgi) first discovered perineuronal networks in 1893, but back then he misunderstood their function. Golgi called the network “corset” and said that they, most likely, prevented the exchange of messages between neurons. The study of Sontheimer denies it. The scientist, on the contrary, found that network support messaging. Neurons covered with perineuronal nets, have less capacity of the membrane and the ability to store electric charge and so can run boost and reload up to two times faster than neseccary neurons.
When they suddenly lose their perineural network, the results can be disastrous: by applying this enzyme to the brain without the tumor, the scientists saw that most of the enzymatic degradation of the perineuronal nets was enough to trigger seizures — even when the neurons remained intact.
Now the attention of researchers focused on the role of perineural network can play in other forms of acquired epilepsy, for example, as a result of head injury or infections of the brain, that will bring them closer to the creation of an effective medication.
“We decided 125 years the mystery of neurology! That’s what basic science to keep an open and observant mind and to answer old and new questions,” says Sontheimer.
According to the world health organization, more than 50 million people worldwide suffer from epilepsy, a third of which are not susceptible to known antiepileptic treatments.