Low-frequency activation of the NMDA receptor system can prevent the induction of LTP.
In rat hippocampal slices bathed in Mg2(+)-free medium tetanic stimulation generally failed to elicit long-term potentiation (LTP) in the Schaffer collateral-commissural pathway. However, LTP could be induced in the same slices following the re-introduction of 1 mM Mg2+. In Mg2(+)-free medium, LTP could be induced in the presence of 20 microM D-2-amino-5-phosphonovalerate (APV) but was blocked by increasing the APV concentration to 200 microM. The lower concentration of APV is sufficient to prevent N-methyl-D-aspartate (NMDA) receptor activation during low-frequency transmission but not during the tetanus. We suggest therefore, that certain types of activation of the NMDA receptor system can disable the LTP induction mechanism.
Coan
E J
EJ
Department of Pharmacology, School of Medical Sciences, University of Bristol, U.K.
Irving
A J
AJ
Collingridge
G L
GL
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D015536:Down-Regulation / Q000187:drug effects; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D066298:In Vitro Techniques; D008274:Magnesium / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology*; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*
D016194:Receptors, N-Methyl-D-Aspartate; D015763:2-Amino-5-phosphonovalerate; D008274:Magnesium