The role of specific ions in glutamate neurotoxicity.

When the chick embryo retina is incubated in balanced salt solution containing glutamate (Glu) in 1 mM concentration, a neurodegenerative reaction occurs within 30 min. Here we report that the neurotoxic action of Glu on retinal neurons is dependent on the presence of Na+ and Cl-, but not Ca2+, in the incubation medium. Also, we report that depolarizing concentrations of K+ can induce a severe cytotoxic reaction in chick retina which, like the depolarization-linked neurotoxicity of Glu, is a Cl- dependent phenomenon.