The reversible change of GluR2 RNA editing in gerbil hippocampus in courseof ischemic tolerance

The ischemic tolerance is known to show protective effects on the neurons a nd the restricted Ca2+ influx through Ca2+ channels might be involved. In a lpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, r ibonucleic acid (RNA) editing of the GluR2 subunit determines receptor dese nsitization and Ca2+ permeability. The authors investigated the effect of i schemic tolerance on the messenger RNA editing of Q/R and R/G sites of GluR 2 subunit in hippocampus. It was found that the rate of RNA editing in Q/R site showed no change (100% edited), whereas that in R/G site decreased sig nificantly (83.3% normal editing level to 60.4%) at day 3 (preconditioning period) and returned to normal level at day 14 (after preconditioning perio d). Further investigation revealed that the decrease of editing rate in isc hemic tolerance resulted mainly from the decrease of editing in CA1 area.