Melanin-concentrating hormone, hippocampal nitric oxide levels and memory retention

Peptides. 2002 Dec;23(12):2213-21. doi: 10.1016/s0196-9781(02)00252-8.


The present study attempts to determine, if the effect of melanin-concentrating hormone (MCH) upon memory retention is correlated with changes in nitric oxide synthase (NOS) activity and tissue levels of nitric oxide (NO) and cGMP. We used a behavioral experiment using a step-down inhibitory avoidance test, the biochemical determinations of NO and cGMP, and electrophysiological model. Results of behavioral studies (step-down test) showed that MCH administration reverts the amnesic effects induced by N(G)-nitro-L-arginine (L-NOArg). Moreover, electrophysiological studies demonstrated that L-NOArg did not block the potentiation induced by the peptide. Hippocampal NO and cGMP levels increased after MCH injection.

MeSH terms

  • Animals
  • Behavior, Animal / physiology
  • Cyclic GMP / metabolism
  • Electrophysiology
  • Hippocampus / metabolism*
  • Hypothalamic Hormones / metabolism*
  • Male
  • Melanins / metabolism*
  • Memory / physiology*
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Pituitary Hormones / metabolism*
  • Rats
  • Rats, Wistar


  • Hypothalamic Hormones
  • Melanins
  • Pituitary Hormones
  • Nitric Oxide
  • melanin-concentrating hormone
  • Nitric Oxide Synthase
  • Cyclic GMP