Altered Actions of Memantine and NMDA-Induced Currents in a New Grid2-Deleted Mouse Line

作者:Kumagai Ayako; Fujita Akira; Yokoyama Tomoki; Nonobe Yuki; Hasaba Yasuhiro; Sasaki Tsutomu; Itoh Yumi; Koura Minako; Suzuki Osamu; Adachi Shigeki; Ryo Haruko; Kohara Arihiro; Tripathi Lokesh P; Sanosaka Masato; Fukushima Toshiki; Takahashi Hiroyuki; Kitagawa Kazuo; Nagaoka Yasuo; Kawahara Hidehisa; Mizuguchi Kenji; Nomura Taisei; Matsuda Junichiro; Tabata Toshihide*; Takemori Hiroshi
来源:Genes, 2014, 5(4): 1095-1114.
DOI:10.3390/genes5041095

摘要

Memantine is a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, and is an approved drug for the treatment of moderate-to-severe Alzheimer%26apos;s disease. We identified a mouse strain with a naturally occurring mutation and an ataxic phenotype that presents with severe leg cramps. To investigate the phenotypes of these mutant mice, we screened several phenotype-modulating drugs and found that memantine (10 mg/kg) disrupted the sense of balance in the mutants. Moreover, the mutant mice showed an attenuated optokinetic response (OKR) and impaired OKR learning, which was also observed in wild-type mice treated with memantine. Microsatellite analyses indicated that the Grid2 gene-deletion is responsible for these phenotypes. Patch-clamp analysis showed a relatively small change in NMDA-dependent current in cultured granule cells from Grid2 gene-deleted mice, suggesting that GRID2 is important for correct NMDA receptor function. In general, NMDA receptors are activated after the activation of non-NMDA receptors, such as AMPA receptors, and AMPA receptor dysregulation also occurs in Grid2 mutant mice. Indeed, the AMPA treatment enhanced memantine susceptibility in wild-type mice, which was indicated by balance sense and OKR impairments. The present study explores a new role for GRID2 and highlights the adverse effects of memantine in different genetic backgrounds.

  • 出版日期2014-12