NMDA subunits cloning

Non-NMDA ionotropic glutamate receptors (the majority sodium channel containing) can be subdivided into a-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) (comprising cloned subunits GluRl ) and kainate (GluR5-7, KAl-2) preferring receptors, with native receptors most likely to comprise either homo- or heteromeric pentamers of these subunits. 

Furthermore, in rodents a member of a third class of NMDA receptor subunits (NR3A) has been cloned (Sucher et al., 1995). Expression of this NR3A subunit together with NR1 and NR2 subunits has been shown to cause in vitro an attenuation of the NMDA-induced ion fluxes and consequently NR3A knock-out mice show in vivo enhanced NMDA receptor activity (Das et al., 1998). Meanwhile a second member (NR3B) of this third class of subunit with comparable features has been cloned from mouse genome (Nishi et al., 2001). 

Ikeda, K., Nakasawa, M., Mori, H., Araki, K., Sakimura, K., Watanabe, M., Inoue, Y., Mishina, M. Cloning and expression of the epsilon 4 subunit of the NMDA receptor channel, FEBS Lett. 1992, 313, 34-38. 

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