Morphological, molecular, and functional characterization of mouse glutamatergic myenteric neurons

• DOI: 10.1101/2023.09.18.558146
• Publication Date: 2023-09-19T04:55:18Z
• Authors: Jia Liu; Shaopeng Zhang; Sharareh Emadi; Tiantian Guo; Longtu Chen; Bin Feng
• Keywords: Enteric Nervous System; Cell bodies

Abstract The enteric nervous system (ENS) functions largely independently of the central (CNS). Correspondingly, glutamate, dominant neurotransmitter in CNS and sensory afferents, is not a primary ENS. Only fraction (approximately 2%) myenteric neurons mouse distal colon rectum (colorectum) are positive for vesicular glutamate transporter type 2 (VGLUT2), structure function which remain undetermined. Here, we systematically characterized VGLUT2-positive (VGLUT2-ENs) through sparse labeling with adeno-associated virus, single-cell mRNA sequencing (scRNA-seq), GCaMP6f calcium imaging. Our results reveal that majority VGLUT2-ENs (29 out 31, 93.5%) exhibited Dogiel I morphology single aborally projecting axon; most axons (26 29, 89.7%) between 4 10 mm long, each traversing 19 to 34 ganglia. These anatomical features exclude from being intrinsic afferent or motor neurons. scRNA-seq conducted on 52 suggests different expression profiles conventional descending interneurons. Ex vivo recordings flattened colorectum indicate almost all VGLUT2-EN (181 215, 84.2%) indirectly activated by colorectal stretch via nicotinic cholinergic neural transmission. In conclusion, functionally unique group long traverse multiple ganglia mechanical stretch. This knowledge will provide solid foundation subsequent studies potential interactions extrinsic afferents glutamatergic neurotransmission. New & Noteworthy We (EN), although constituting small total EN, homogeneously expressed ganglia, slight concentration at intermediate region rectum. coincides entry zone into colorectum. Given stretch, they likely participate visceral nociception transmission afferents.