Functional properties of the NMDA receptor in the lateral amygdala: a comparison with those in the hippocampal CA1 region

Abstract

The amygdala is a crucial brain structure for the acquisition and expression of fear memory.The N-methyl-D-aspartate (NMDA)-type glutamate receptor channel, composed of the NR1 and NR2 subunits, plays a key role in synaptic plasticity in the CNS. NR2 subunits (NR2A-NR2D) are differentially expressed, depending on developmental stages and brain regions, but their functional roles are still unclear. In this study, we investigated the properties of synaptic NMDA receptors in the lateral nucleus of the amygdala (LA), comparing them with those of synaptic NMDA receptors in the CA1. We show that the electrophysiological properties of NMDA receptors and NR2A/NR2B ratio in the LA are distict from those of NMDA receptors in the CA1 and that the NR2B subunit contributes to synaptic transmission and long-term potentiation (LTP) induction more significantly in the LA than in the CA1. Our data suggest that these properties of NMDA receptors and the NR2B subunit in the LA are responsible for amygdala synaptic function and plasticity. [J Physiol Sci. 2007;57 Suppl:S19]