Myenteric Plexus Neurons (Auerbach'S Plexus) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
The myenteric plexus, also known as Auerbach's plexus, is a major component of the enteric nervous system (ENS) located between the circular and longitudinal muscle layers of the gastrointestinal tract. It is the primary regulator of gut motility, coordinating peristalsis and segmental contractions. The myenteric plexus is emerging as a key player in the gut-brain axis and has been implicated in neurodegenerative diseases, particularly Parkinson's disease.
¶ Anatomy and Structure
- Situated between the outer longitudinal and inner circular muscle layers
- Extends from the esophagus to the internal anal sphincter
- Most prominent in the small intestine and colon
| Component |
Description |
| Ganglion |
Collections of neuronal cell bodies |
| Interconnecting fibers |
Connect ganglia into network |
| Fiber bundles |
Project to muscle layers |
| Glial cells |
Support and protect neurons |
The myenteric plexus contains:
- Motor neurons - control smooth muscle contraction
- Interneurons - coordinate between neurons
- Sensory neurons - detect stretch and chemical changes
- Secretomotor neurons - control glandular secretion
| Neuron Type |
Neurotransmitter |
Function |
| Cholinergic excitatory |
Acetylcholine |
Muscle contraction |
| Nitrergic inhibitory |
Nitric oxide |
Muscle relaxation |
| Purinergic |
ATP |
Fast inhibitory transmission |
| Peptidergic |
VIP, CGRP |
Slow inhibitory transmission |
| Serotonergic |
5-HT |
Modulate motility |
-
Primary afferent neurons (sensory)
- Detect stretch
- Monitor chemical environment
- Transduce to enteric and central nervous systems
-
Interneurons
- Propagate signals orally and anally
- Coordinate peristaltic reflex
- Process local circuits
-
Motor neurons
- Excitatory (choline)
- Inhibitory (NO, VIP)
- Control peristalsis and tone
The myenteric plexus coordinates the peristaltic reflex:
- Luminal distension activates sensory neurons
- Sensory signal propagated to interneurons
- Oral excitation (cholinergic) + anal inhibition (nitrergic)
- Coordinated wave of contraction and relaxation
- Circular muscle motor patterns
- Mixed with peristalsis
- Maximum mixing of contents
- Cyclic pattern during fasting
- Clears debris from intestine
- Controlled by myenteric plexus
-
Vagus nerve (parasympathetic)
- Myenteric → vagal afferents → brainstem → higher brain regions
-
Spinal afferents (sympathetic)
- Myenteric → dorsal root ganglia → spinal cord
-
Enteric-to-central signaling
- Via ENS neurons
- To vagal nucleus
- To hypothalamic nuclei
- Acetylcholine
- Dopamine
- Serotonin
- GABA
- Noradpinephrine
- Nitric oxide
Lewy Pathology in ENS:
- α-Synuclein inclusions found in myenteric neurons
- May precede brain involvement by years
- Explains early GI symptoms (constipation)
- "Body-first" propagation hypothesis
GI Dysmotility:
- Constipation (most common early symptom)
- Delayed gastric emptying
- Small intestinal bacterial overgrowth
- Correlates with disease severity
Mechanisms:
- α-Synuclein misfolding in ENS neurons
- Impaired autophagy-lysosomal pathway
- Mitochondrial dysfunction
- Neuroinflammation
-
Gut Motility Changes:
- Constipation common in AD
- May relate to cholinergic dysfunction
-
Autonomic Dysfunction:
- Vagal degeneration
- Affects both CNS and ENS
-
Gut-Brain Signaling:
- Cholinergic anti-inflammatory pathway
- Altered in AD
- GI dysmotility reported
- Autonomic involvement
- Enteric nervous system changes
- May relate to disease progression
-
Multiple System Atrophy:
- Severe GI dysfunction
- Autonomic failure
-
Dementia with Lewy Bodies:
- Similar to PD ENS involvement
-
Huntington's Disease:
- GI symptoms common
- May involve ENS
- TUJ1 (βIII-tubulin) - neuronal marker
- HuC/D - neuronal nuclei
- nNOS (neuronal nitric oxide synthase) - inhibitory motor neurons
- ChAT (choline acetyltransferase) - excitatory motor neurons
- VIP - peptidergic neurons
- CGRP - sensory neurons
- S100β - enteric glial cells
- GFAP - enteric glia
- Rectal biopsy for α-synuclein
- Colonic transit time
- Anorectal manometry
- Small bowel manometry
-
Prokinetic agents:
- Metoclopramide (dopamine antagonist)
- Erythromycin (motilin agonist)
-
Targeting ENS:
- Restore dopaminergic signaling
- Enhance nitrergic function
-
Lifestyle interventions:
- Dietary fiber
- Hydration
- Exercise
-
Future Therapies:
- Stem cell-based treatments
- Gene therapy
- α-Synuclein targeting
The study of Myenteric Plexus Neurons (Auerbach'S Plexus) has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Furness JB. (2012). "The enteric nervous system and neurogastroenterology." Nat Rev Gastroenterol Hepatol. 9(5):286-294.
- Breen KC. (2012). "Alpha-synuclein and the gastrointestinal tract." J Parkinsons Dis. 2(2):87-96.
- Braak H, et al. (2006). "Gastric alpha-synuclein immunoreactive inclusions in Meissner's and Auerbach's plexuses in cases staged for Parkinson's disease-related brain pathology." Neurosci Lett. 396(1):67-72.
- Travagli RA, et al. (2020). "Neuronal networks in the enteric nervous system." Auton Neurosci. 225:102756.
- Cheng LK, et al. (2010). "Computer model of the enteric nervous system." Neurogastroenterol Motil. 22(7):740-752.
- Cersosimo MG, Benarroch EE. (2012). "Neural control of the gastrointestinal tract: implications for Parkinson disease." Mov Disord. 27(10):1232-1238.
- Pan-Montojo FJ, et al. (2012). "Progression of Parkinson's disease pathology in the enteric nervous system." J Parkinsons Dis. 2(1):1-19.