医師の一分

アクセスカウンタ

zoom RSS 難治てんかんの根本原因を特定?

<<   作成日時 : 2009/12/08 01:03   >>

なるほど(納得、参考になった、ヘー) ブログ気持玉 6 / トラックバック 0 / コメント 0

 ニューカッスル大のチームが薬物療法に抵抗する難治性てんかんの根本原因を明らかにしたという。
 化学的というより間違った電気的な接続により引きおこされるので、従来の薬剤では効果がないという。世界で約4500万人の患者の新しい治療への道を開く可能性がある。
 てんかん患者の約30%は薬物療法に失敗し、外科的治療を受ける人もいる。
 てんかんの患者の脳切除組織から、個々の神経細胞とそのネットワークの電気的活動を記録したところ、けいれんの前駆症状と思われる非常に早い速波 oscillation VFO と呼ばれるノイズが記録された。非シナプス経由の錐体細胞間のネットワークから出現しており皮質のてんかん起源となっていると推定される。
----------------------------------------------------
Page last updated at 04:02 GMT, Sunday, 6 December 2009
Likely cause of drug-resistant epilepsy revealed
http://news.bbc.co.uk/2/hi/health/8385790.stm

画像Neurons
In epilepsy, the neurons misfire and create abnormal electrical activity

Experts believe they have uncovered the root cause of "stubborn" epilepsy that fails to respond to drug treatment.

Tests on patients' brain tissue revealed some seizures are caused by electrical connections between nerve cells rather than chemical ones.

This faulty wiring would explain why traditional drugs are useless and why some patients have to resort to surgery, say the UK researchers.

Their work appears in Proceedings of the National Academy of Sciences.

Dr Mark Cunningham and his team at Newcastle University hope the findings will open the door to new treatments for the disease which affects an estimated 45 million people worldwide.

In almost 30% of epilepsy patients drug treatment fails and some resort to surgery to remove the brain tissue responsible for the condition.

Brain signals

The researchers took brain tissue removed from people with epilepsy and in the lab were able to coax it to behave as if it was still part of the living brain.

They were then able to record electrical signals from individual neurons and networks of neurons in the samples.

We hope that this research will move us closer to effective treatment for more people with epilepsy in future
Simon Wigglesworth of Epilepsy Action

Comparing this with normal brain tissue activity, they managed to record an underlying 'noise' - a particular type of brain wave, or oscillation, which occurs in the intact epileptic human brain and which scientists believe is a precursor to an epileptic seizure.

They then found that rather than being controlled by chemical signals which most conventional anti-epileptic drugs target, this oscillation relies on direct electrical connections.

Dr Cunningham said the next step would be to understand what it is that triggers the transition between the underlying epileptic state of the brain cells and the fast oscillations that are responsible for causing a seizure.

Simon Wigglesworth of Epilepsy Action said: "This is exciting news for people whose epilepsy cannot be controlled by medication and an important development in our understanding of the condition.

"Currently, there is no treatment to cure epilepsy other than surgery, which at the moment is only effective for small numbers.

"We hope that this research will move us closer to effective treatment".

A spokeswoman for Epilepsy Research UK described the research as "very promising".

---------------------------------------------------
A nonsynaptic mechanism underlying interictal discharges in human epileptic neocortex

PNAS published online before print December 4, 2009, doi:10.1073/pnas.0912652107

1. Anita K. Roopuna,
2. Jennifer D. Simonottob,
3. Michelle L. Piercea,
4. Alistair Jenkinsc,
5. Claire Nicholsonc,
6. Ian S. Schofieldc,
7. Roger G. Whittakera,
8. Marcus Kaisera,b,d,
9. Miles A. Whittingtona,
10. Roger D. Traube and
11. Mark O. Cunninghama,1

+ Author Affiliations

1.
aInstitute of Neuroscience, The Medical School, Framlington Place, Newcastle University, Newcastle-upon-Tyne NE2 4HH, UK
2.
bSchool of Computing Science, Claremont Tower, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK
3.
cRegional Neurosciences Centre, Newcastle General Hospital, Newcastle-upon-Tyne NE4 6BE, UK
4.
dDepartment of Brain and Cognitive Sciences, Seoul National University, Seoul 151-746, Korea
5.
eIBM T.J. Watson Research Center, Yorktown Heights, NY 10598

1.

Communicated by Nancy J. Kopell, Boston University, Boston, MA, November 7, 2009 (received for review September 15, 2009)

Abstract

Very fast oscillations (VFOs, >80 Hz) are important for physiological brain processes and, in excess, with certain epilepsies. Putative mechanisms for VFO include interneuron spiking and network activity in coupled pyramidal cell axons. It is not known whether either, or both, of these apply in pathophysiological conditions. Spontaneously occurring interictal discharges occur in human tissue in vitro, resected from neocortical epileptic foci. VFO associated with these discharges was manifest in both field potential and, with phase delay, in excitatory synaptic inputs to fast spiking interneurons. Recruitment of somatic pyramidal cell and interneuron spiking was low, with no correlation between VFO power and synaptic inputs to principal cells. Reducing synaptic inhibition failed to affect VFO occurrence, but they were abolished by reduced gap junction conductance. These data suggest a lack of a causal role for interneurons, and favor a nonsynaptic pyramidal cell network origin for VFO in epileptic human neocortex.


テーマ

関連テーマ 一覧


月別リンク

ブログ気持玉

クリックして気持ちを伝えよう!
ログインしてクリックすれば、自分のブログへのリンクが付きます。
→ログインへ
気持玉数 : 6
なるほど(納得、参考になった、ヘー) なるほど(納得、参考になった、ヘー) なるほど(納得、参考になった、ヘー) なるほど(納得、参考になった、ヘー)
驚いた
面白い

トラックバック(0件)

タイトル (本文) ブログ名/日時

トラックバック用URL help


自分のブログにトラックバック記事作成(会員用) help

タイトル
本 文

コメント(0件)

内 容 ニックネーム/日時

コメントする help

ニックネーム
本 文
難治てんかんの根本原因を特定? 医師の一分/BIGLOBEウェブリブログ
文字サイズ:       閉じる