The mouse neocortical slice: preparation and responses to excitatory amino acids.

1. An improved method of preparing wedges of cerebral cortex and corpus callosum from 500 microM thick coronal sections using mouse brain is described. 2. The characteristics of mixing in the two compartment baths is fully reported. 3. Cortical tissue could be depolarized relative to callosal tissue by superfusion of N-methyl-D-aspartate (NMDA), quinolinate, kainate or quisqualate. 4. At higher concentrations of agonists the depolarization was followed by a small hyperpolarization. This hyperpolarization was abolished by 5 microM ouabain. 5. Neither TTX (1 microM) nor bicuculline (50-62.5 microM) significantly affected the amplitude of the responses to the excitatory amino acids. 6. Responses to NMDA and quinolinate were selectively reduced by magnesium ions, 2-amino-5-phosphonovalerate or ketamine.