Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How seizures progress to epilepsy in the young

09.12.2005


A major mystery in epilepsy research has been why infants are more prone to seizures than adults and how those seizures progress to chronic epilepsy. Now, researchers have discovered that central to those seizures in the developing brain are neurons triggered by the neurotransmitter GABA. They say their findings could lead to new ways to treat seizures in newborns. Also, they say, their findings suggest that the use of drugs that enhance GABA action may be particularly harmful to the newborn brain.



In adults, epilepsy is caused by hyperactivation of neuronal receptors triggered by the neurotransmitter glutamate. This excess activation unleashes the storm of uncontrolled nerve cell firing that underlies epilepsy. In contrast, in adults the neurotransmitter GABA acts on its receptors to inhibit neurons. Loss of this inhibition is also involved in epilepsy.

Neurotransmitters such as glutamate and GABA are chemical signals that one neuron launches at its neighbor across connections called synapses.


Yehezkel Ben-Ari and colleagues decided to explore a possible role of GABA-controlled neural circuitry in seizures in infant animals because it was known that, while GABA excites immature neurons, it changes to an inhibitory neurotransmitter in adult neurons.

In their experiments described in the December 8, 2005, issue of Neuron, they used a preparation in which they isolated in three separate compartments the left and right hippocampi of baby rats and the nerve fibers connecting them. The researchers studied the hippocampus because it is the brain area central to epilepsy.

With this experimental arrangement, they could use drugs to block GABA receptors and/or induce electrical seizure in one hippocampus and analyze whether such manipulations influenced seizure activity in the other. Such a spreading influence is a sign that individual seizures have caused development of a chronic epileptic state.

Their experiments revealed that the GABA-triggered neurons were involved in seizures in the immature brains and also that those seizures did lead to development of an epileptic state. They found that these GABA-triggered seizures featured so-called "fast oscillations" of electrical activity that are required to transform a "naive" network of neurons into an epileptic one.

In other experiments comparing immature and adult rat hippocampi, they found that although GABA-triggered neurons were also involved in seizures in adult brains, they were not required for development of epilepsy, as they were in immature hippocampi.

The researchers concluded that their studies showed that fast oscillations involved in seizures "are also directly implicated in epileptogenesis in the immature brain and lead to the production of a persistent chronic epileptic condition."

As the neuronal network matures, however, the density of synapses triggered by glutamate increases and the contribution of GABA-triggered synapses to fast oscillations and development of epilepsy decreases, they wrote.

"This information may be important both for understanding the deleterious consequences of seizures in newborns and for developing new therapeutic treatments for seizures in young infants," wrote Ben-Ari and colleagues. "Specifically, the permissive action of excitatory GABA suggests that GABA-acting drugs may exert deleterious actions at an early developmental stage in humans."

Heidi Hardman | EurekAlert!
Further information:
http://www.neuron.org
http://www.cell.com

More articles from Life Sciences:

nachricht Hunting pathogens at full force
22.03.2017 | Helmholtz-Zentrum für Infektionsforschung

nachricht A 155 carat diamond with 92 mm diameter
22.03.2017 | Universität Augsburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>