Fatty acid amide hydrolase (FAAH) knockout mice exhibit enhanced acquisition of an aversive, but not of an appetitive, Barnes maze task

Neurobiol Learn Mem. 2009 Nov;92(4):597-601. doi: 10.1016/j.nlm.2009.06.001. Epub 2009 Jun 11.

Abstract

It is well established that genetic deletion or pharmacological inhibition of the CB(1) receptor disrupts extinction learning in aversive conditioning tasks, but not in appetitive tasks. Consistent with these findings is that genetic deletion or pharmacological inhibition of fatty acid amide hydrolase (FAAH), the primary catabolic enzyme of the endogenous cannabinoid anandamide (AEA), accelerates acquisition as well as extinction in aversive conditioning tasks. However, it is unknown whether FAAH blockade will affect acquisition in an appetitive conditioning task. Therefore, in the present study, we assessed FAAH (-/-) and (+/+) mice in appetitive and aversive Barnes maze conditioning procedures. Here we report that FAAH (-/-) mice displayed accelerated acquisition rates in an aversively-motivated, but not in the appetitively-motivated, Barnes maze task. The CB(1) receptor antagonist, rimonabant attenuated enhanced acquisition in the aversive procedure, consistent with the idea that elevated AEA levels mediate this apparent nootropic effect. These findings support the hypothesis that stimulation of the endocannabinoid system enhances learned behavior in aversive, but not appetitive, conditioning paradigms.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Amidohydrolases / genetics
  • Amidohydrolases / physiology*
  • Analysis of Variance
  • Animals
  • Appetitive Behavior / physiology*
  • Arachidonic Acids / metabolism
  • Arachidonic Acids / pharmacology
  • Avoidance Learning / physiology*
  • Cannabinoid Receptor Modulators / pharmacology
  • Conditioning, Classical / physiology
  • Endocannabinoids
  • Maze Learning / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Piperidines / pharmacology
  • Polyunsaturated Alkamides / metabolism
  • Polyunsaturated Alkamides / pharmacology
  • Pyrazoles / pharmacology
  • Receptor, Cannabinoid, CB1 / antagonists & inhibitors
  • Receptor, Cannabinoid, CB1 / metabolism*
  • Rimonabant

Substances

  • Arachidonic Acids
  • Cannabinoid Receptor Modulators
  • Endocannabinoids
  • Piperidines
  • Polyunsaturated Alkamides
  • Pyrazoles
  • Receptor, Cannabinoid, CB1
  • Amidohydrolases
  • fatty-acid amide hydrolase
  • Rimonabant
  • anandamide