Molecular and functional asymmetry in Cckar-expressing vagal sensory neurons.

The vagus nerves are important carriers of sensory information from the viscera to the brain. Emerging evidence suggests that sensory signaling through the right, but not the left, vagus nerve evokes striatal dopamine release and reinforces appetitive behaviors. However, the extent to which differential gene expression within vagal sensory neurons may underlie this asymmetric reward-related signaling is unknown. Here, we use single-nucleus RNA sequencing, in situ hybridization, and calcium imaging to identify a single cluster of neurons, defined by co-expression of Chrna3 (nicotinic acetylcholine receptor subunit 3) and Cckar (cholecystokinin 1 receptor), that is preferentially expressed in the right nodose ganglia of rats and mice. This neuronal population also expresses several genes implicated in digestive signaling, including Glp1r and Sctr, consistent with a gut-innervating subtype. Our results suggest that right-biased expression of this unique chemosensing vagal cell type may contribute to asymmetric encoding of interoceptive rewards by the vagus nerves.