Figure 4

UBP145 prevents tPA-promoted NMDA-induced Ca²⁺influx in cortical neurons. Two successive 30 second exposures to NMDA (50 μM) lead to a rapid and reproducible Ca²⁺ influx in cultured cortical neurons (A-D; n = 3 independent cultures; n = 150 cells). Cells were then incubated for 45 minutes with tPA alone (20 μg/mL) or with UBP145 0.2 μM. NMDA exposure was performed again. In contrast to tPA alone (B, E), when co-incubated with UBP145, tPA did not promote NMDA-induced Ca²⁺ influx in cortical neurons (C, E). UBP145 alone at 0.2 μM did not affect NMDA-induced Ca²⁺ influx (D, E). For each condition, illustrative images (during NMDA stimulation before and after treatment) are provided at the top of calcium recordings (A-D).