PROTEIN-KINASE INHIBITOR, H-7, DIRECTLY AFFECTS N-METHYL-D-ASPARTATE RECEPTOR CHANNELS

Compounds commonly used to modify protein phosphorylation have been found to interact directly with K channels, Ca channels, and acetylcholine receptor channels. We report that a general protein kinase inhibitor, H-7, directly affects N-methyl-D-aspartate (NMDA) receptors independent of protein kinase activity. Single-channel records in the presence of H-7 have fewer bursts of activity, and the currents are interrupted in a voltage-dependent manner by brief closures. Hippocampal whole-cell currents induced by NMDA are not decreased by H-7, in part, because the single-channel currents have longer burst lengths that compensate for the brief closures.