Endogenous cannabinoids trigger the depolarization-induced suppression of excitation in the lateral amygdala

Learn Mem. 2009 Dec 30;17(1):43-9. doi: 10.1101/lm.1663410. Print 2010 Jan.

Abstract

The amygdala is a key area of the brain where the emotional memories are stored throughout the lifespan. It is well established that synapses in the lateral nucleus of amygdala (LA) can undergo long-term potentiation, a putative cellular correlate of learning and memory. However, a type of short-term synaptic plasticity, known as depolarization-induced suppression of excitation (DSE), has not been studied previously in the amygdala in general and in the LA in particular. In this study we aimed to prove either the absence or the presence of this phenomenon in the LA. Our data demonstrate for the first time that DSE is present in the LA and that it modulates the cortical excitatory synaptic input into this region. The existence of this type of retrograde neurotransmission in glutamatergic pyramidal neurons of the LA suggests that the axonal terminals of cortical inputs do possess functional type 1 cannabinoid receptors, and provides a novel insight regarding inputs into the LA. Further experiments indeed revealed endocannabinoids as the messenger for this retrograde signaling in the LA. In conclusion, the DSE may play a functional role in synaptic plasticity and related emotional memory processing in the LA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amygdala / drug effects
  • Amygdala / physiology*
  • Animals
  • Calcium / physiology
  • Cannabinoid Receptor Modulators / physiology*
  • Electrophysiology
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Miniature Postsynaptic Potentials / drug effects
  • Miniature Postsynaptic Potentials / physiology
  • Neural Inhibition / drug effects
  • Neural Inhibition / physiology*
  • Neuronal Plasticity / drug effects
  • Neuronal Plasticity / physiology*
  • Neurons / drug effects
  • Neurons / physiology*
  • Patch-Clamp Techniques
  • Piperidines / pharmacology
  • Pyrazoles / pharmacology
  • Receptor, Cannabinoid, CB1 / antagonists & inhibitors
  • Receptor, Cannabinoid, CB1 / physiology
  • Signal Processing, Computer-Assisted
  • Synapses / drug effects
  • Synapses / physiology
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology

Substances

  • Cannabinoid Receptor Modulators
  • Piperidines
  • Pyrazoles
  • Receptor, Cannabinoid, CB1
  • AM 251
  • Calcium