Rat neocortical slice preparation for electrophysiological and pharmacological studies

A procedure for the preparation and maintenance of rat neocortical slices for in vitro electrophysiological and pharmacological studies is described. Application of L-glutamate increased the spontaneous firing rate of the cells in these slices. Acetylcholine (ACh) slightly elevated the firing in some cells, while showing no effect on others. The agent, however, produced a prolonged facilitation of the effects of glutamate. N-ethyl maleimide (NEM), a sulphydryl reagent, did not alter the firing rate when applied by itself or along with ACh, but it potentiated the firing rate when administered along with glutamate. It is possible that NEM either interfered with glutamate uptake or altered the tissue responsiveness to the amino acid. The present results do not distinguish between these two possibilities.