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 Good preparation is half the digestion
15.11.2018 | Max-Planck-Institut für Stoffwechselforschung

nachricht How the gut ‘talks’ to brown fat
16.11.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland

15.11.2018 | Earth Sciences

When electric fields make spins swirl

15.11.2018 | Physics and Astronomy

Discovery of a cool super-Earth

15.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>