Synaptic plasticity and NO-cGMP-PKG signaling coordinately regulate ERK-driven gene expression in the lateral amygdala and in the auditory thalamus following Pavlovian fear conditioning

Learn Mem. 2010 Mar 29;17(4):221-35. doi: 10.1101/lm.1592510. Print 2010 Apr.

Abstract

We have recently hypothesized that NO-cGMP-PKG signaling in the lateral nucleus of the amygdala (LA) during auditory fear conditioning coordinately regulates ERK-driven transcriptional changes in both auditory thalamic (MGm/PIN) and LA neurons that serve to promote pre- and postsynaptic alterations at thalamo-LA synapses, respectively. In the present series of experiments, we show that N-methyl-D-aspartate receptor (NMDAR)-driven synaptic plasticity and NO-cGMP-PKG signaling in the LA regulate the training-induced expression of ERK and the ERK-driven immediate early genes (IEGs) Arc/Arg3.1, c-Fos, and EGR-1 in the LA and the MGm/PIN. Rats receiving intra-LA infusion of the NR2B selective antagonist Ifenprodil, the NOS inhibitor 7-Ni, or the PKG inhibitor Rp-8-Br-PET-cGMPS exhibited significant decreases in ERK activation and in the training-induced expression of all three IEGs in the LA and MGm/PIN while intra-LA infusion of the PKG activator 8-Br-cGMP had the opposite effect. Remarkably, those rats given intra-LA infusion of the membrane impermeable NO scavenger c-PTIO exhibited significant decreases in ERK activation and ERK-driven IEG expression in the MGm/PIN, but not in the LA. Together with our previous experiments, these results suggest that synaptic plasticity and the NO-cGMP-PKG signaling pathway promote fear memory consolidation, in part, by regulating ERK-driven transcription in both the LA and the MGm/PIN. They further suggest that synaptic plasticity in the LA during fear conditioning promotes ERK-driven transcription in MGm/PIN neurons via NO-driven "retrograde signaling."

Publication types

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

MeSH terms

  • Acoustic Stimulation / adverse effects
  • Amygdala / drug effects
  • Amygdala / physiology*
  • Animals
  • Behavior, Animal
  • Conditioning, Classical / drug effects
  • Conditioning, Classical / physiology*
  • Cyclic GMP / metabolism
  • Cyclic GMP-Dependent Protein Kinases / metabolism
  • Enzyme Inhibitors / pharmacology
  • Excitatory Amino Acid Antagonists / pharmacology
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Fear* / drug effects
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology*
  • Male
  • Models, Biological
  • Neuronal Plasticity / drug effects
  • Neuronal Plasticity / genetics
  • Neuronal Plasticity / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • Thalamus / drug effects
  • Thalamus / physiology*
  • Time Factors

Substances

  • Enzyme Inhibitors
  • Excitatory Amino Acid Antagonists
  • Cyclic GMP-Dependent Protein Kinases
  • Extracellular Signal-Regulated MAP Kinases
  • Cyclic GMP