A test of the spine resistance hypothesis for LTP expression.
Long-term potentiation (LTP) consists of an enhanced response to released transmitter by the quisqualate/AMPA subclass of glutamate receptors with little change in the slower currents generated by the NMDA receptor subclass. Recent computer simulations suggest that a decrease in the resistance of dendritic spines would selectively augment fast synaptic currents and this could produce the pattern of results found with LTP. The present experiments tested this hypothesis by asking whether non-NMDA responses slowed by low temperature to resemble NMDA responses could express LTP. Slow non-NMDA responses recorded at 25 degrees C did express LTP, indicating that the time courses of NMDA responses cannot explain why they do not express LTP. The results, therefore, do not support the hypothesis that spine resistance changes are responsible for the enhanced transmission.
Larson
J
J
Center for the Neurobiology of Learning and Memory, University of California, Irvine 92717.
Lynch
G
G
D000818:Animals; D003080:Cold Temperature; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D007051:Ibotenic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D016202:N-Methylaspartate / Q000494:pharmacology; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D018091:Receptors, AMPA; D017981:Receptors, Neurotransmitter / Q000187:drug effects; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
D018091:Receptors, AMPA; D017981:Receptors, Neurotransmitter; D007051:Ibotenic Acid; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D016318:Quisqualic Acid