Cell-Type Specificity of Neuronal Excitability and Morphology in the Central Amygdala.

Anisha P Adke,Yarimar Carrasquillo,Yae K Sugimura,Torri D Wilson,Aleisha Khan,Hye-Sook Ahn,Spring Valdivia,Jordan J Becker,Santiago Martinez Gonzalez

doi:10.1523/eneuro.0402-20.2020

Abstract

Central amygdala (CeA) neurons expressing protein kinase Cδ (PKCδ+) or somatostatin (Som+) differentially modulate diverse behaviors. The underlying features supporting cell-type-specific function in the CeA, however, remain unknown. Using whole-cell patch-clamp electrophysiology in acute mouse brain slices and biocytin-based neuronal reconstructions, we demonstrate that neuronal morphology and relative excitability are two distinguishing features between Som+ and PKCδ+ neurons in the laterocapsular subdivision of the CeA (CeLC). Som+ neurons, for example, are more excitable, compact, and with more complex dendritic arborizations than PKCδ+ neurons. Cell size, intrinsic membrane properties, and anatomic localization were further shown to correlate with cell-type-specific differences in excitability. Lastly, in the context of neuropathic pain, we show a shift in the excitability equilibrium between PKCδ+ and Som+ neurons, suggesting that imbalances in the relative output of these cells underlie maladaptive changes in behaviors. Together, our results identify fundamentally important distinguishing features of PKCδ+ and Som+ cells that support cell-type-specific function in the CeA.

Highlights

The laterocapsular subdivision of the central nucleus (CeA) of the amygdala (CeLC) has received increasing interest because of its widespread function in mediating innate, as well as learned, adaptive and maladaptiveReceived September 18, 2020; accepted October 12, 2020; First published November 13, 2020
Using a mouse model of neuropathic pain, we tested whether perturbations known to alter CeLC-dependent behavioral outputs would result in a shift in the relative excitability of these two CeLC cell types. Using this cell-type-specific approach, we demonstrated that PKCd 1 and Som1 neurons have distinct electrophysiological and morphologic properties and that the differences in the excitability of these cells are occluded in the context of neuropathic pain
Our analyses showed that Rin is significantly higher in Som1 (160.5 6 10.23 MV) compared with PKCd 1 late-firing cells (131.4 6 12.51 MV; Fig. 3D), suggesting that differences in subthreshold conductances might contribute to the differences in excitability observed in PKCd 1 and Som1 neurons

Summary

Introduction

The laterocapsular subdivision of the central nucleus (CeA) of the amygdala (CeLC) has received increasing interest because of its widespread function in mediating innate, as well as learned, adaptive and maladaptiveReceived September 18, 2020; accepted October 12, 2020; First published November 13, 2020. Veinante et al, 2013), anxiety, and drug reward and relapse in rodent models (Gilpin et al, 2015; Venniro et al, 2017, 2018), to name a few. This diverse span of function is mirrored by the genetic, physiological and morphologic heterogeneity in CeA neuron subtypes (Martina et al, 1999; Schiess et al, 1999; Janak and Tye, 2015)

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Results

Conclusion