Oxytocin receptor specifically marks ventromedial intercalated cells of the mouse amygdala

Intercalated cells (ITC) of the amygdala gate fear expression and extinction, and are anatomically and functionally divided into dorsomedial (dm; fear expression) and ventromedial (vm; fear extinction) populations. The molecular basis of this functional dichotomy remains incompletely defined. Here, we reanalysed a published single-cell RNA-sequencing dataset of the mouse amygdala (Hochgerner et al., 2023) and examined the neuromodulatory receptor repertoire of four Foxp2+ ITC clusters (GABA-1 to GABA-4). Using an unbiased Gene Ontology-derived receptor list (705 receptors) and FindAllMarkers with default parameters and Benjamini-Hochberg correction, we identified 74 cluster-enriched receptors (FDR < 0.05). The vm cluster (GABA-1) was defined by Oxtr, completely cluster-specific (expressed in 43% of vm cells and 0% of other ITC), together with Htr2c, Cnr1, Htr3a, Oprk1 and Sstr2. The dm-candidate cluster (GABA-4) instead expressed a largely non-overlapping set of receptors (Adora1, Drd3, Hrh3, Oprk1, Chrna7 and Adra1a). This receptor-level asymmetry, and in particular the vm-specific oxytocin receptor, provides a candidate molecular handle on the functional distinction between vm and dm ITC in fear processing.