[Effects of ischemia/reperfusion on the phosphotyrosine proteins contents in hippocampus]

The effects of three drugs including ketamine(KT), a noncompetitive antagonist of NMDA receptor (NR), nifedipine(ND), a voltage gated calcium channel (VGCC) antagonist and 6, 7dinitroquinoxaline -2, 3-dione(DNQX), a non-NMDA receptor antagonist on the contents of phospho-tyrosine proteins (p-tyr-pr) in the synaptosomal(P2), the crude membrane (P3), and the cytosolic (S3) fractions of hippocampus in forebrain ischemia of mongolian gerbils were studied.

(1) the contents of p-tyr-pr in all three fractions (P2, P3, S3) decreased 15 min after ischemia, but the contents of p-tyr-pr in S3 fraction decreased more obviously than the others did, With the increase of reperfusion time, the contents of p-tyr-pr in all of these fractions recovered gradually, but the p-tyr-pr in S3 fraction increased more rapidly among them, in the P2 fraction, the contents of p-tyr-pr increased slowly, but significantly and sustained longer during reperfusion when compared with that of P3 did. (2) The increase in p-tyr-pr contents induced by cerebral ischemia/reperfusion was partially antagonisted by KT and ND administration prior to cerebral ischemia, under these conditions, DNQX has no effect on it.

the increase of p-tyr-Pr contents induced by cerebral ischemia/reperfusion is related to NR channel and L-type VGCC, but not to non-NR channel.