Figure 2.

Release of LDH, a marker of neuronal injury, 24 h after a 30-min washout of synaptic blockers. (a) PD098059, at the concentrations indicated, was added 1 h before, during, and 24 h after a 30-min washout of kynurenate. PD098059 reduced the release of LDH with an EC₅₀ of ≈10 μM, close to the IC₅₀ for MEK1 inhibition (mean ± SEM, three to seven cultures per dose). (b) Adding PD098059 (40 μM) only during the washout of synaptic blockers (PD During) prevented the release of LDH and was as effective as adding it before, during and after the washout (PD Before, During, & After). PD098059 did not block the release of LDH if it was added only after the washout of synaptic blockers (PD After). In this experiment, PD098059 was only slightly less effective than 5 mM kynurenate in preventing the release of LDH (mean ± SEM, three cultures per condition).