Nitric oxide synthase inhibitors block long-term potentiation induced by weak but not strong tetanic stimulation at physiological brain temperatures in rat hippocampal slices

Neurosci Lett. 1993 Sep 17;160(1):85-8. doi: 10.1016/0304-3940(93)90919-c.


Nitric oxide synthase (NOS) inhibitors have been shown to block long-term synaptic enhancements in the mammalian hippocampus. This effect has been somewhat controversial, however, showing sensitivity to both temperature and stimulus strength. We have demonstrated a differential effect of the NOS inhibitor L-NG-nitroarginine (NOArg) on long-term potentiation (LTP) induced by weak and strong tetanic stimulation in slices of rat hippocampus. NOArg prevented LTP induction by a weak tetanus that produced stable potentiation in control slices, while the NOS inhibitor was without effect when strong tetani were used. These results suggest that nitric oxide (NO) produced as a result of tetanic stimulation plays a role in adjusting the threshold of LTP induction, but is not necessary for establishing synaptic enhancement under conditions of strong synaptic activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Oxidoreductases / antagonists & inhibitors*
  • Animals
  • Arginine / analogs & derivatives
  • Arginine / pharmacology
  • Electric Stimulation
  • Hippocampus / drug effects*
  • Hippocampus / physiology
  • In Vitro Techniques
  • Long-Term Potentiation / drug effects*
  • Male
  • Nitric Oxide Synthase
  • Nitroarginine
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Temperature


  • Receptors, N-Methyl-D-Aspartate
  • Nitroarginine
  • Arginine
  • Nitric Oxide Synthase
  • Amino Acid Oxidoreductases