Vagal Afferent Innervation of the Enteric Nervous System
Sue Ritter, Robert C. Ritter, Charles D. Barnes in Neuroanatomy and Physiology of Abdominal Vagal Afferents, 2020
The digestive tract is innervated by a complex neural network, referred to as the enteric nervous system (ENS), which consists of numerous intrinsic neurons that are organized into two major ganglionated plexuses.18,21,23,69 The myenteric or Auerbach’s plexus lies between the longitudinal and circular muscle layers, and the submucosal or Meissner’s plexus is located within the submucosa. Intramural neurons give rise to nerve fibers that connect the ganglia within the plexus and the ganglionated plexuses to each other; fibers emerging from the ganglionated plexuses innervate the different layers of the gut and blood vessels. The majority of enteric axons originates from intrinsic neurons, which represent the chief component of the nervous apparatus controlling digestive functions. This is supported by the observation that decentralization causes little effect on most of the spontaneous and reflex activities, which in turn provides strong evidence for the existence of sensory receptors, intrinsic primary afferent neurons, interneurons and motor neurons within the ENS (see Furness and Costa19 for review).
Neuro–Endocrine–Immune Dysfunction in the Chronic Pain Patient
Sahar Swidan, Matthew Bennett in Advanced Therapeutics in Pain Medicine, 2020
The autonomic nervous system is made up of the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system (ENS). The enteric nervous system directly controls the gastrointestinal (GI) tract.6 A key role of the autonomic system is the regulation of acute inflammatory responses at local and systemic levels.7 The sympathetic nervous system secretes catecholamines such as epinephrine and norepinephrine which induces changes in bone marrow, thymus, spleen, and lymph nodes. Catecholamines can regulate immune proliferation, cytolytic activity, cytokine release, antibody release, and chemotaxis by binding to adrenoreceptors on lymphoid organs and immune cells. Norepinephrine and epinephrine increase lymphocyte proliferation and inhibit cytotoxic activity. Dopamine inhibits both proliferation and cytotoxic activity.8 In addition, peripheral vasoconstriction occurs which can result in chronic muscular ischemia.
What's Causing My Gut Symptoms?
Melissa G. Hunt, Aaron T. Beck in Reclaim Your Life From IBS, 2022
Did you know that you have a brain in your gut? Well, not really. But many gastroenterologists point out that the gut has its own nervous system that has just as many nerve cells, or neurons, as the spinal cord. The enteric nervous system consists of a number of different types of neurons each of which do different jobs. For example, motor neurons, embedded in the muscles in the digestive tract, control motility – the smooth contractions of muscles that move food through the system at just the right speed (a process called peristalsis) and the mixing, squishing actions that help break food down, mix it up, expose it to digestive juices, and make it available for absorption (called segmentation contractions). Sensory neurons do lots of different jobs, including sensing or “tasting” different chemicals in the food you have eaten (like glucose and the amino acids that make up proteins), conveying information about stretch and tension in the walls of the stomach and intestines, and also relaying the perception of pain.
Communication between the gut microbiota and peripheral nervous system in health and chronic disease
Published in Gut Microbes, 2022
Tyler M. Cook, Virginie Mansuy-Aubert
The enteric nervous system is comprised of sensory, motor, and interneurons organized into networks or plexuses located within the gut, which are capable of operating independently of the CNS. The submucosal plexus lies between the mucosa and circular muscle, and it regulates secretion and blood flow.39 Enteric neurons between the circular and longitudinal muscle make up the myenteric plexus (Auerbach plexus), which controls gut motility by action on smooth muscle. Enteric sensory neurons known as IPANs (intrinsic primary afferent neurons) detect various chemicals or distension caused by a food bolus, and then coordinate the electrical activity of submucosal and myenteric neurons. Finally, interneurons link the activity of ascending and descending motor networks to allow the “little brain” of the gut to function autonomously (Figure 3).39,51 The enteric nervous system is also supported by local glial cells, which also respond to changes in gut microbiota signaling,52 but we will focus on enteric neurons in this review.
Naringenin modulates Cobalt activities on gut motility through mechanosensors and serotonin signalling
Published in Biomarkers, 2023
Adeola Temitope Salami, Ademola Adetokubo Oyagbemi, Moyosore Victoria Alabi, Samuel Babafemi Olaleye
The small intestine, is a part of the gastrointestinal tract responsible for nutritional absorption (from food), immunologic and endocrine functions (Denbow 2015, Mark and Bouwmeester 2017) besides motility. Motility within the small intestine enhances mixing, transit of secretions and digested contents from the stomach, and removal or ridding of ingested harmful or toxic substances not absorbed. Hunt et al. (1985) demonstrated that gastric emptying is hinged on the volume, composition, osmolality and caloric density of food ingested which is coordinated by the pyloric sphincter and duodenum activities. Mechanosensors (Alcaino et al. 2017) found along the small intestine aid these activities; examples of these include epithelial cells such as myenteric neurons, interstitial cells of Cajal, smooth muscle, enterochromaffin cells, glia, etc. The digestive system is propelled by the enteric nervous system (ENS) while gut hormones also regulate functioning of the intestine such as motility, secretion, cell proliferation, digestion and absorption (Ma and Lee 2020). Gastric emptying is regulated by its’ inhibitory and excitatory hormones which are also released from both the intestine and pancreas thus mediating or relating food intake, satiety, energy metabolism to gastric emptying (Goyal et al. 2019).
Gut microbiota-motility interregulation: insights from in vivo, ex vivo and in silico studies
Published in Gut Microbes, 2022
Barbora Waclawiková, Agnese Codutti, Karen Alim, Sahar El Aidy
The primary neurotransmitters of the excitatory neurons are the neuropeptides, acetylcholine and tachykinins, acetylcholine responses are mediated by the muscarinic receptors (M2 and M3), tachykinins (substance P and neurokinin A) bind to NK1 and NK2 receptors and activate pathways similar to those that involve acetylcholine.19–28 The inhibitory neurons constitute multiple transmitters, including nitric oxide, vasoactive intestinal peptide (VIP), and ATP-like transmitters.17,29 The nitric oxide is considered as the predominant inhibitory neurotransmitter, and deficits in transmission are observed in its absence as demonstrated in models where nitric oxide synthase is knocked out.2,30 The role of the enteric nervous system in the regulation of gut motility has been extensively reviewed elsewhere.3 Here, we will focus on the less well-studied role of the gut microbiota and its metabolites as a key regulator of the gut motility.
Related Knowledge Centers
- Autonomic Nervous System
- Gastrointestinal Tract
- Neural Crest
- Neurotransmitter
- Sympathetic Nervous System
- Parasympathetic Nervous System
- Vagus Nerve
- Neuron
- Prevertebral Ganglia
- Acetylcholine