Genetic labeling of axo-axonic cells in the basolateral amygdala. (May 2022)

• Record Type: Journal Article
• Authors: Nakashima, Miki; Ikegaya, Yuji; Morikawa, Shota
• Is Part Of: Neuroscience research. Volume 178(2022)
• Page Start: 33
• Page End: 40
• Publication Date: 2022-05
• Subjects: Axo-axonic cell -- BLA -- Vipr2 -- Interneuron -- Parvalbumin; Neurosciences -- Research -- Periodicals; Neurosciences -- Research -- Japan -- Periodicals; Neurology -- Periodicals; Neurosciences -- Periodicals; Neurosciences -- Recherche -- Périodiques; Neurosciences -- Recherche -- Japon -- Périodiques; Neurosciences -- Research; Japan; Periodicals; 612.8
• DOI: 10.1016/j.neures.2022.02.002
• Languages: English
• ISSNs: 0168-0102

Abstract

Abstract: GABAergic neurons are classified into multiple subtypes based on morphology, physiological properties, and gene expression profiles. Although traditionally defined axo-axonic cells (AACs) are a unique type of interneuron that expresses parvalbumin and innervates the axon initial segment (AIS) of pyramidal neurons, a genetic marker for AACs in the basolateral amygdala (BLA) has not been identified. Here, we show that vasoactive intestinal peptide receptor 2 ( Vipr2 )-expressing interneurons exhibit anatomical and electrophysiological properties of AACs in the BLA. Using a reporter mouse expressing fluorescent proteins specifically in Vipr2 + cells, we analyzed the distribution, postsynaptic targeting and electrophysical properties of Vipr2 + cells in the BLA. More than half of the Vipr2 + cells showed parvalbumin immunoreactivity and innervated the AIS of pyramidal neurons in the BLA of Vipr2-tdTomato mice. Notably, most of the Vipr2 + cells showed fast-spiking properties. Furthermore, the use of a Cre-dependent adeno-associated virus led to more selective labeling of AACs in the BLA. These results suggest that AACs are genetically identifiable in the BLA without anatomical or physiological analysis. Highlights: Vipr2-expressing interneurons exhibit anatomical and electrophysiological properties of axo-axonic cells in the BLA. Almost all axo-axonic synapses are Vipr2-positive in the BLA. The use of a Cre-dependent AAV leads to more selective labeling of axo-axonic cells in the BLA.