Involvement of amino acids, opioids, nitric oxide, and NMDA receptors in learning and memory consolidation in crickets

Pharmacol Biochem Behav. 1994 Mar;47(3):493-6. doi: 10.1016/0091-3057(94)90149-x.


The effect of injections of selected amino acids and of N-methyl-D-aspartate (NMDA); morphine; and NMDA, nitric oxide (NO), and opioid inhibitors given before a maze-learning was investigated. Thirsty crickets (Pteronemobius sp) were trained to turn only to one side of a symmetrical Y-shaped maze using reinforcements with water. The insects retained the learned task 24 h later. N2 anoxia applied immediately after training produced retrograde amnesia. Injections of alanine (Ala), arginine (Arg), glutamine (Gln), morphine, or NMDA prior to training blocked the amnesic action of anoxia. Naloxone, an opioid antagonist, blocked long-term memory formation, but not learning, whereas hemoglobin or 2-amino-5-phosphonovaleric acid (APV), NO and NMDA antagonists respectively, blocked both. The antiamnesic effect of Morphine and Arg, but not that of Ala or NMDA was blocked by naloxone. The results suggest involvement of NMDA receptors and NO and thus of long-term potentiation phenomena in learning and in memory consolidation, whereas other neuromodulatory systems related to Arg, and opiate receptors, are only involved in memory consolidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology
  • Amino Acids / pharmacology
  • Amino Acids / physiology*
  • Animals
  • Conditioning, Operant / drug effects
  • Endorphins / antagonists & inhibitors
  • Endorphins / physiology*
  • Female
  • Gryllidae / physiology*
  • Hemoglobins / pharmacology
  • Learning / drug effects*
  • Memory / drug effects*
  • N-Methylaspartate / antagonists & inhibitors
  • N-Methylaspartate / pharmacology
  • Naloxone / pharmacology
  • Nitric Oxide / antagonists & inhibitors
  • Nitric Oxide / physiology*
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / physiology


  • Amino Acids
  • Endorphins
  • Hemoglobins
  • Receptors, N-Methyl-D-Aspartate
  • Nitric Oxide
  • Naloxone
  • N-Methylaspartate
  • 2-Amino-5-phosphonovalerate