Amygdala Basolateral Nuclear ¦Â Receptors, Prefrontal Cortex Nmda Receptor Nr2b Subunit In Memory

It is known thatβ-adrenoceptors(ARs) in the basolateral nucleus of amygdala(BLA) play an essential role in fear memory formation.However,the cellular and subcellular distributions ofβ1- andβ2-ARs in the BLA are poorly understood,nor are their roles in fear memory consolidation.Here,we report that bothβ1- andβ2-ARs are predominantly expressed in BLA neurons but not in astrocytes.Whileβ1-ARs are distributed in the cell membrane and cytoplasm of neurons,β2-ARs are localized not only in the cell membrane and cytoplasm but in the nucleus as well.Intra-BLA infusion of theβ1- AR antagonist metoprolol or theβ2-AR antagonist ICI118551 produced a severe deficit in 24-h auditory fear memory,leaving 1-h memory intact.The present results indicate thatβ1- andβ2-ARs in the BLA have differential subcellular localizations and are both required for consolidation of auditory fear memory. NR2B subunits of NMDA receptor are intimately associated with the development of central nervous system and are essentially required for synaptic plasticity and hippocampus-dependent memory.The prefrontal cortex(PFC) plays a critical role in higher cognitive functions,especially working memory.However,the role of NR2B in working memory function is poorly understood.Here,we report that NR2B subunits are expressed in the PFC of rat and monkey,especially in synaptosomes of this region. Intra-PFC infusion of the NR2B antagonist Ro25-6981 produced a severe deficit in T-maze delayed-alternation working memory both in adult mice and rats.These results indicate that prefrontal cortical NR2B is involved in working memory.