β1- and β2-Adrenoceptors in basolateral nucleus of amygdala and their roles in consolidation of fear memory in rats

✍ Scribed by Li-Li Qu; Nan-Nan Guo; Bao-Ming Li

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 520 KB
• Volume: 18
• Category: Article
• ISSN: 1050-9631
• DOI: 10.1002/hipo.20478

✦ Synopsis

Abstract

It is known that β‐adrenoceptor (AR) in the basolateral nucleus of amygdala (BLA) plays an essential role in fear memory formation. However, the cellular and subcellular distributions of β1‐ and β2‐ARs in the BLA and their roles in fear memory formation are poorly understood. Here, we report that both β1‐ and β2‐ARs are predominantly expressed in BLA neurons but not in astrocytes. β1‐AR is distributed in the cell membrane and cytoplasm of neurons, whereas β2‐AR is localized not only in the cell membrane and cytoplasm but also in the nucleus. Intra‐BLA infusion of the β1‐AR antagonist metoprolol and atenolol or the β2‐AR antagonist ICI118551 and butoxamine produces a severe deficit in 24‐h auditory fear memory, leaving 1‐h memory intact. Western‐blot analysis reveals that the protein level of cytoplasmic β1‐AR significantly increases 2‐ and 4‐h postconditioning, whereas that of cytoplasmic or nuclear β2‐AR is unchanged. The present results indicate that β1‐ and β2‐ARs in the BLA have differential subcellular localizations and both are required for the consolidation of auditory fear memory. © 2008 Wiley‐Liss, Inc.