Long-term potentiation differentially affects two components of synaptic responses in hippocampus.
We have used low magnesium concentrations and the specific antagonist D-2-amino-5-phosphonopentanoate (D-AP5) to estimate the effects of long-term potentiation (LTP) on the N-methyl-D-aspartate (NMDA) and non-NMDA receptor-mediated components of postsynaptic responses. LTP induction resulted in a considerably larger potentiation of non-NMDA as opposed to NMDA receptor-related currents. Increasing the size of postsynaptic potentials with greater stimulation currents or with paired-pulse facilitation produced opposite effects; i.e., those aspects of the response dependent on NMDA receptors increased to a greater degree than did those components mediated by non-NMDA receptors. These results pose new constraints on hypotheses about the locus and nature of LTP and strongly suggest that postsynaptic modifications are part of the effect.
D015763:2-Amino-5-phosphonovalerate; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D016202:N-Methylaspartate; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology; D012016:Reference Values; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D001224:Aspartic Acid; D016202:N-Methylaspartate; D015763:2-Amino-5-phosphonovalerate; D014633:Valine