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

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.