Synaptic cell adhesion molecule <i>Cdh6</i> identifies a class of sensory neurons with novel functions in colonic motility.

Abstract

Intrinsic sensory neurons are an essential part of the enteric nervous system (ENS) and play a crucial role in gastrointestinal tract motility and digestion. Neuronal subtypes in the ENS have been distinguished by their electrophysiological properties, morphology, and expression of characteristic markers, notably neurotransmitters and neuropeptides. Here, we investigated synaptic cell adhesion molecules as novel cell-type markers in the ENS. Our work identifies two type II classic cadherins, <i>Cdh6</i> and <i>Cdh8,</i> specific to sensory neurons in the mouse colon. We show that <i>Cdh6+</i> neurons demonstrate all other distinguishing classifications of enteric sensory neurons including marker expression of <i>Calcb</i> and <i>Nmu</i>, Dogiel type II morphology and AH-type electrophysiology and <i>I_H</i> current. Optogenetic activation of <i>Cdh6+</i> sensory neurons in distal colon evokes retrograde colonic motor complexes (CMCs), while pharmacologic blockade of rhythmicity-associated current <i>I_H</i> disrupts the spontaneous generation of CMCs. These findings provide the first demonstration of selective activation of a single neurochemical and functional class of enteric neurons and demonstrate a functional and critical role for sensory neurons in the generation of CMCs.