Fast desensitizing kainate-gated current resolved in whole-cell experiments on isolated rat hippocampal neurons

In whole-cell concentration-jump experiments on dissociated rat hippocampal neurons the existence of a fast desensitizing component of a kainate-gated current was demonstrated. More than 90% of all neurons tested possessed such a receptor. Electrophysiological and pharmacological data suggest an association of this fast kainate-gated current with that mediated through a combination of subunits forming a low-affinity "(RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolopropionic acid (AMPA)-preferring' receptor. Kinetic data suggest the existence of a compact spatial location of fast desensitizing "AMPA-preferring' receptors which are naturally expressed on the surface of the neurons. An AMPA-insensitive current component mediated through fast desensitizing high-affinity kainate receptors was not observed.