Glutamate receptors induce a burst of superoxide via activation of nitric oxide synthase in arginine-depleted neurons.

Abstract

We have previously shown in cultured cerebellar granule neurons (Lafon-Cazal, M., Pietri, S., Culcasi, M., and Bockaert, J. (1993) Nature 364, 535-537) that upon N-methyl-D-aspartate stimulation, a nitric oxide synthase (NOS)-independent, arachidonic acid-dependent generation of superoxide free radicals (O2-.) is observed after a lag time of 10-15 min. Using the electron spin resonance spin trapping technique, we show that N-methyl-D-aspartate stimulation produced a more rapid burst of O2-. in L-arginine (L-Arg)-depleted neurons. These O2-. radicals are synthesized by NOS. KCl and kainate, which also stimulated NOS in these neurons, produced this rapid burst of O2-., which was blocked as follows: (a) in the presence of L-NG-nitro-arginine (L-Narg), and (b) by L-Arg repletion. This burst of O2-. was arachidonic acid-independent, and its time course was similar to that of nitric oxide production. It was also responsible for a weak but significant cell death that was suppressed by L-Narg and L-Arg.