Results
Differentiated RGC-5 cells were pretreated with 100
μM agmatine for 2 h, and then exposed to 1.0 mM H2O2
for 16 h for induction of oxidative stress. After agmatine
pretreatment, the cytotoxicity of H2O2 declined from above
50 to approximately 30% (Figure 1A,B).
Neither yohimbine nor NMDA, at any concentration,
had any significant effect on oxidative stress-induced cell
death (data not shown); 10 nM yohimbine and 100 μM
NMDA were used for further experiments. While yohimbine
almost completely blocked the protective effects of agmatine
pretreatment (Figure 1A), NMDA did not (Figure 1B).
To evaluate the contribution of NMDA receptor signaling,
the protective effect of agmatine was compared to that
of MK-801. MK-801 did not significantly affect the H2O2-
induced cytotoxicity of RGC-5 cells (Figure 1C).