Figure 5. tPA-induced delayed preconditioning.

(A–C) Mean survival in hippocampal neurons exposed to OGD conditions (55 minutes) 24 hours after treatment with 60 nM tPA or 1 μM itPA (A); or with a combination of 60 nM tPA and 140 nM α₂-antiplasmin, 1.4 μM aprotinin (Apro), 20 mM EACA, 100 nM RAP, 10 μM MK-801, or 50 μM DL-AP5; or with 200 nM plasminogen (Plg) alone or 100 nM plasmin alone or RAP alone (B and C). In A: *P < 0.05 compared with cells under normoxic conditions; **P < 0.05 compared with untreated neurons under OGD conditions and with cells treated with itPA. In B and C: *P < 0.05 compared with untreated cells under OGD conditions; **P < 0.05 compared with untreated cells; ***P < 0.05 compared with cells treated with tPA or plasmin alone. n = 20 for each observation in A and B and n = 15 in C. Error bars denote SD. (D) Western blot analysis detecting the expression of the NR2A subunit of the NMDAR in hippocampal neurons incubated with 60 nM tPA or 100 nM plasmin. (E) Mean neuronal survival following incubation with 250 μM KA alone or 24 hours after treatment with 60 nM tPA. *P < 0.05 compared with untreated cells; **P < 0.05 compared with KA-treated cells. n = 10. Error bars denote SD in all panels.