BioAcyl Corp

The sympathetic nervous system is shown in dark yellow, with one of a bilateral chain of paraspinal ganglia. Parasympathetic connections of the vagus nerve and sacral and cranial outflows are shown in blue. Sensory afferent neurons are also carried in each of these pathways, with the predominantly sensory nodose ganglion of the vagus shown prior to its brainstem entry point and spinal cord pathways of the spinal afferent intestinal neurons in the inset. Sensory neurons comprise most nerve fibers of the vagus nerve.

The different layers of the intestine are shown with the submucosal and myenteric plexus. The intestinal reflex is generated through coordinated oral contraction and aboral relaxation with stimulatory neurons (green) predominantly transmitting acetylcholine (ACh) or substance P (SP) and nitric oxide (NO) or vasoactive intestinal peptide (VIP) inhibitory neurons (red). These receive signals from sensory neurons extending to the mucosa (brown) or from extrinsic autonomic effector neurons (not shown). Secretomotor neurons with cell bodies predominantly in the submucosal plexus are shown in purple. Insets show (1) enteroendocrine cells sensing luminal intestinal contents including microbial metabolites and IL-33 and (2) nociceptor reflex with antidromal production of calcitonin gene-related peptide (CGRP) modulating sampling activity of Peyer’s patch M cells and production of mucus by epithelial goblet cells.