Transcriptional or translational inhibition blocks low dose NMDA-mediated cell death.

Glutamate toxicity in nerve cells has been well documented and may play a role in a broad spectrum of neurological and ophthalmic diseases. Recent work in several laboratories has suggested that an apoptotic-like mechanism may be implicated in glutamate toxicity under certain circumstances. We therefore studied the effects of transcriptional and translational inhibition on glutamate-mediated cell death in retinal ganglion cells. We now report that either cycloheximide or actinomycin D can, even when added 2 h after the initial excitotoxic insult, save retinal ganglion cells from low dose glutamate toxicity. However, cycloheximide or actinomycin D are unable to prevent glutamate-mediated death at higher concentrations of excitotoxin. This result indicates that at low doses, the neurotoxic effects of glutamate may develop through an apoptotic-like mechanism.