alpha-melanocyte-stimulating hormone (a-MSH) reverses impairment of memory reconsolidation induced by Interleukin-1 beta (IL-1 beta) hippocampal infusions

MACHADO I; GONZALEZ P; SCHIÖTH H; LASAGA M; SCIMONELLI T

PEPTIDES

ELSEVIER SCIENCE INC

Año: 2010 vol. 31 p. 2141 - 2144

0196-9781

Interleukin-1beta (IL-1b) significantly influences cognitive processes. Treatments which raise the level of IL-1b in the brain impair memory consolidation in contextual fear conditioning. However, the effect of IL-1b on memory reconsolidation has not yet been established. The melanocortin a-melanocyte-stimulating hormone (a-MSH) exerts potent anti-inflammatory actions by antagonizing the effect of pro-inflammatory cytokines. Five subtypes of melanocortin receptors (MC1R-MC5R) have been identified, of which MC3R and MC4R are predominant in the central nervous system. The present experiments show that the injection of IL-1b (5ng/0.25ul) in dorsal hippocampus up to 30 min after re-exposition to the context decreases freezing during the contextual fear test. Impairment of memory reconsolidation was reversed by treatment with a-MSH (0.05ug/0.25ul). Administration of the MC4 receptor antagonist HS014 (0.5ug/0.25ul) blocked the effect of a-MSH. These results suggest that IL-1b may influence memory reconsolidation and that activation of central MC4R could lead to improve cognitive performance.