Glutamate induces long-term increase in the frequency of single N-methyl- d-aspartate channel openings in hippocampal CA1 neurons examined in situ

Abstract

Long-term potentiation is currently a leading candidate for a physiological memory mechanism in CNS. The interpretation of this phenomenon is contradictory in many respects. 2,8,10,11 However, there is clear evidence that long-term potentiation is critically dependent on activation of N-methyl- d-aspartate receptors. 3 Recently it has been shown that extracellularly applied glutamate also induces long-lasting changes in the properties of synaptic transmission in the hippocampus that can be attributed to long-term potentiation. 7 The involvement of presynaptic mechanisms has been reported. 6,9 Here we demonstrate a definite increase in both the open time and open-state probability of N-methyl- d-aspartate-operated channels, induced by prolonged application of glutamate to hippocampal slices.