BRAIN and NERVE－神経研究の進歩61巻7号

2009年07月発行

特集 脳腫瘍研究の最前線―遺伝子解析から治療まで

グリアとグリアの腫瘍におけるグルタミン酸受容体の新たな役割

著者： 石内勝吾¹

所属機関： ¹琉球大学医学部脳神経外科

ページ範囲：P.753 - P.764

文献概要

はじめに

　AMPA型グルタミン酸受容体は，速い速度の神経伝達に関与し記憶・学習など高次脳機能に重要な役割を担っている。この受容体は，4つのサブユニットから形成され（GluR1-4またはGluR A-D; encoded by genes GRIA 1-4），これらのサブユニットの単独またはさまざまな組み合わせからなる4量体と考えられている。

　チャネルのカルシウム透過性はGluR2の有無によって決定され，成熟した神経細胞に発現するAMPA型グルタミン酸受容体がGluR2を保有しカルシウム不透過型であるのに対し，小脳分子層に局在するベルグマングリア^1）や胎児脳および悪性脳腫瘍の代表である膠芽腫での発現は，GluR2を欠くカルシウム透過性AMPA型受容体であることが知られている^2）。

　後2者ではさらに，GluR2の変異体で高いカルシウム透過性を示すGluR2（Q）が混在して発現する場合がある^3）。このようなグリアやグリオーマに発現しているグルタミン酸受容体について，その機能的役割が徐々に明らかになりつつある。

　本稿では，イオン型グルタミン酸受容体のうちの，特にグリオーマにおけるカルシウム透過性AMPA型受容体に焦点をあて，正常グリア細胞における生物学的意義とグリオーマにおける増殖・遊走・浸潤性の分子機構について概説する。

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