MILD KAINATE TOXICITY PRODUCES SELECTIVE MOTONEURON DEATH WITH MARKEDACTIVATION OF CA2-PERMEABLE AMPA()KAINATE RECEPTORS/

Motoneuron death could be produced by higher sensitivity to excitotoxi city during the development and pathological conditions. We report her e that in ventral spinal cord cultures mild kainate exposure (12.5 mu M, 20 min or 100 mu M, 2.5 min) induced selective cobalt stain of moto neurons, indicating a specific Ca2+ entry through the Ca2+-permeable A MPA/kainate receptors. This result was associated with a selective mot oneuron death as previously described. In these cultures, motoneuron i mmunoreactivity for the Ca2+ buffering protein, calretinin was negativ e. These findings suggest that the selective motoneuron death due to a mild excitotoxic insult could be linked to a marked Ca2+ influx assoc iated with the lack of some Ca2+ buffering proteins. (C) 1998 Elsevier Science B.V. All rights reserved.