Inhibition of long-term potentiation by NMDA-mediated nitric oxide release

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Science  28 Aug 1992:
Vol. 257, Issue 5074, pp. 1273-1276
DOI: 10.1126/science.1519065


Activation of N-methyl-D-aspartate (NMDA) receptors before tetanic stimulation blocks long-term potentiation (LTP) in the CA1 region of the hippocampus. This NMDA-mediated inhibition of LTP can be reversed by the nitric oxide (NO) inhibitors L-NG-monomethyl-arginine or hemoglobin and mimicked by sodium nitroprusside. These results indicate that the timing of NO release relative to high-frequency activation of CA1 synapses may be an important determinant of LTP generation and suggest that NO may play a positive or negative modulatory role in LTP depending on prior events at the tetanized synapse and the ambient concentration of excitatory amino acids.