Mitogen-activated protein kinase in the amygdala plays a critical role in lithium chloride-induced taste aversion learning

Neurobiol Learn Mem. 2012 Jan;97(1):132-9. doi: 10.1016/j.nlm.2011.10.005. Epub 2011 Nov 9.


The intracellular mitogen-activated protein kinase (MAPK) pathway in the brain is necessary for the formation of a variety of memories including conditioned taste aversion (CTA) learning. However, the functional role of MAPK activation in the amygdala during lithium chloride (LiCl)-induced CTA learning has not been established. In the present study, we investigated if local microinjection of SL327, a MAPK kinase inhibitor, into the rat amygdala could alleviate LiCl-induced CTA learning. Our results revealed that acute administration of a high dose of LiCl (0.15M, 12 ml/kg, i.p.) rapidly increased the level of phosphorylated MAPK (pMAPK)-positive cells in the central nucleus of the amygdala (CeA) and nucleus of the solitary tract (NTS) of rats as measured by immunohistochemistry. Local microinjection of SL327 (1 μg/0.5 μl/hemisphere) into the CeA 10 min before LiCl administration decreased both the strength of LiCl-induced CTA paired with 0.125% saccharin and the level of LiCl-induced pMAPK-positive cells in the CeA, but not in the NTS. Our data suggest that the intracellular signaling cascade of the MAPK pathway in the CeA plays a critical role in the processing of visceral information induced by LiCl for CTA learning.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoacetonitrile / analogs & derivatives
  • Aminoacetonitrile / pharmacology
  • Amygdala / drug effects
  • Amygdala / metabolism
  • Amygdala / physiology*
  • Animals
  • Avoidance Learning / drug effects
  • Avoidance Learning / physiology*
  • Conditioning, Psychological / drug effects
  • Conditioning, Psychological / physiology*
  • Lithium Chloride / pharmacology
  • Male
  • Microinjections
  • Mitogen-Activated Protein Kinases / metabolism*
  • Phosphorylation / drug effects
  • Phosphorylation / physiology
  • Protease Inhibitors / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Solitary Nucleus / metabolism
  • Taste / physiology*


  • Protease Inhibitors
  • SL 327
  • Aminoacetonitrile
  • Mitogen-Activated Protein Kinases
  • Lithium Chloride