Glutamate receptors communicate with Na+/K+-ATPase in rat cerebellum granule cells: demonstration of differences in the action of several metabotropic and ionotropic glutamate agonists on intracellular reactive oxygen species and the sodium pump.

Two glutamate receptor agonists, NMDA (N-methyl-D-aspartic acid) and ACPD (cis-(1S/3R)-1-aminocyclopentane- 1,3-dicarboxylic acid), induce the reactive oxygen species (ROS) production in rat cerebellum granule cells, whereas the third one, 3-HPG (3-hydroxyphenylglycine), decreases this parameter. The simultaneous presence of 3-HPG, together with NMDA or ACPD, prevents the generation of ROS by neuronal cells. A similar effect of these ligands on Na+/K+-ATPase can be demonstrated: NMDA and ACPD inhibited the enzyme activity, but 3-HPG activated Na+/K+-ATPase and prevented its inhibition by NMDA or ACPD. In terms of current classification, NMDA is an agonist of ionotropic glutamate receptors of the so-called NMDA class, whereas ACPD and 3-HPG belong to metabotropic agonists, the former primarily being an activator of metabotropic glutamate receptors (mGluRs) of groups 2 and 3, and the latter, that of mGluRs of groups 1 and 5. Thus, the data presented illustrate the existence of diverse mechanisms of the cross talk between Na+/K+-ATPase and different glutamate receptors, as well as that between glutamate receptors of different classes.