Single-channel evidence for glycine and NMDA requirement in NMDA receptor activation.

N-Methyl-D-aspartate (NMDA) receptor dose-response relationships that are based on macroscopic currents suggest that NMDA and a different agonist molecule, glycine, must together activate the channel. Since single-channel recordings have a much higher resolution than whole-cell currents, they provide a highly sensitive test for the absolute requirement of NMDA channel opening for glycine. Rapid application of 10-300 microM NMDA to outside-out patches from cultured cortical neurons evoked substantial single-channel activity in the absence of added glycine.

Burst kinetics of single NMDA receptor currents in cell-attached patches from rat brain cortical neurons in culture.

1. The patch-clamp technique was used to record single-channel currents from cell-attached patches on rat brain cortical neurons in culture. The composition of the open and shut intervals during bursts of openings was studied in N-methyl-D-aspartate (NMDA) receptors exposed to 1 microM NMDA and 10 microM glycine at a membrane potential of -70 mV.

Single-channel currents from diethylpyrocarbonate-modified NMDA receptors in cultured rat brain cortical neurons.

The role of histidine residues in the function of N-methyl-D-aspartate (NMDA)-activated channels was tested with the histidine-modifying reagent diethylpyrocarbonate (DEP) applied to cells and membrane patches from rat brain cortical neurons in culture. Channels in excised outside-out patches that were treated with 3 mM DEP for 15-30 s (pH 6.5) showed an average 3.