Sympathetic Neurons

Sympathetic Neurons

Introduction

<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Sympathetic Neurons</th>
</tr>
<tr>
<td class="label">Cell Type Name</td>
<td>Sympathetic [Neurons](/entities/neurons)</td>
</tr>
<tr>
<td class="label">Allen Atlas ID</td>
<td>Sympathetic ganglia (superior cervical, stellate, thoracic chain)</td>
</tr>
<tr>
<td class="label">Lineage</td>
<td>Neural crest > Sympathoblast > Sympathetic neuron</td>
</tr>
<tr>
<td class="label">Marker Genes</td>
<td>PHOX2B, ASCL1, TH, DBH, PHOX2A, GATA2, HAND2</td>
</tr>
<tr>
<td class="label">Brain Regions</td>
<td>Sympathetic chain ganglia, prevertebral ganglia</td>
</tr>
<tr>
<td class="label">Taxonomy</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology (CL)</td>
<td>[CL:0011103](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0011103)</td>
</tr>
<tr>
<td class="label">Database</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology</td>
<td>[CL:0011103](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0011103)</td>
</tr>
<tr>
<td class="label">Organ</td>
<td>Sympathetic Effect</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>↑ Rate, ↑ contractility</td>
</tr>
<tr>
<td class="label">Lungs</td>
<td>Bronchodilation</td>
</tr>
<tr>
<td class="label">GI tract</td>
<td>↓ Motility,

Sympathetic Neurons

Introduction

<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Sympathetic Neurons</th>
</tr>
<tr>
<td class="label">Cell Type Name</td>
<td>Sympathetic [Neurons](/entities/neurons)</td>
</tr>
<tr>
<td class="label">Allen Atlas ID</td>
<td>Sympathetic ganglia (superior cervical, stellate, thoracic chain)</td>
</tr>
<tr>
<td class="label">Lineage</td>
<td>Neural crest > Sympathoblast > Sympathetic neuron</td>
</tr>
<tr>
<td class="label">Marker Genes</td>
<td>PHOX2B, ASCL1, TH, DBH, PHOX2A, GATA2, HAND2</td>
</tr>
<tr>
<td class="label">Brain Regions</td>
<td>Sympathetic chain ganglia, prevertebral ganglia</td>
</tr>
<tr>
<td class="label">Taxonomy</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology (CL)</td>
<td>[CL:0011103](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0011103)</td>
</tr>
<tr>
<td class="label">Database</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology</td>
<td>[CL:0011103](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0011103)</td>
</tr>
<tr>
<td class="label">Organ</td>
<td>Sympathetic Effect</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>↑ Rate, ↑ contractility</td>
</tr>
<tr>
<td class="label">Lungs</td>
<td>Bronchodilation</td>
</tr>
<tr>
<td class="label">GI tract</td>
<td>↓ Motility, ↓ secretion</td>
</tr>
<tr>
<td class="label">Kidneys</td>
<td>↓ Urine output</td>
</tr>
<tr>
<td class="label">Bladder</td>
<td>Urinary retention</td>
</tr>
<tr>
<td class="label">Liver</td>
<td>Glycogenolysis, gluconeogenesis</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Target</td>
</tr>
<tr>
<td class="label">Midodrine</td>
<td>α1 agonist</td>
</tr>
<tr>
<td class="label">Droxidopa</td>
<td>Norepinephrine prodrug</td>
</tr>
<tr>
<td class="label">Pyridostigmine</td>
<td>AChE inhibitor</td>
</tr>
<tr>
<td class="label">β-blockers</td>
<td>β1</td>
</tr>
<tr>
<td class="label">Clonidine</td>
<td>α2 agonist</td>
</tr>
</table>

Sympathetic Neurons is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Sympathetic neurons are components of the autonomic nervous system that regulate involuntary functions including heart rate, blood pressure, pupil dilation, sweat production, and digestive motility. Postganglionic sympathetic neurons degenerate in autonomic neuropathies, and sympathetic dysfunction is an early feature of [Parkinson's disease](/diseases/parkinsons-disease) and multiple system atrophy. [@goldstein2019]

Overview

Multi-Taxonomy Classification

Taxonomy Database Cross-References

Morphology & Electrophysiology

• Morphology: sympathetic neuron (source: Cell Ontology)
• Morphology can be inferred from Cell Ontology classification

External Database Links

• [Cell Ontology (CL:0011103)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0011103)
• [OBO Foundry (CL:0011103)](http://purl.obolibrary.org/obo/CL_0011103)
• [Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
• [CellxGene Census](https://cellxgene.cziscience.com/)
• [Human Cell Atlas](https://www.humancellatlas.org/)

Taxonomy & Classification

External Database Links

• [Cell Ontology (CL:0011103)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0011103)
• [OBO Foundry (CL:0011103)](http://purl.obolibrary.org/obo/CL_0011103)
• [Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
• [CellxGene Census](https://cellxgene.cziscience.com/)

Morphology and Markers

The sympathetic nervous system has two neurons in series:

Preganglionic Neurons

• Location: Spinal cord (T1-L2, intermediolateral cell column)
• Axon: Thinly myelinated (B fibers), preganglionic
• Neurotransmitter: [Acetylcholine](/entities/acetylcholine) (ACh)
• Receptors: Nicotinic ACh receptors on postganglionic neurons

Postganglionic Neurons

Long, unmyelinated C fibers:

• Cell bodies: In autonomic ganglia (chain or prevertebral)
• Axon length: Can be very long (e.g., to extremities)
• Neurotransmitter: Norepinephrine (most), ACh (sweat glands)
• Receptors: Adrenergic (α1, α2, β1-3), muscarinic (M3)

Molecular Markers

• PHOX2B: Master transcription factor for sympathetic neurons
• ASCL1 (MASH1): Neural crest specification
• TH (Tyrosine hydroxylase): Rate-limiting catecholamine synthesis
• DBH (Dopamine β-hydroxylase): Norepinephrine synthesis
• PNMT (Phenylethanolamine N-methyltransferase): Epinephrine synthesis
• Phox2a, GATA2, HAND2: Transcription factors
• SLC18A2 (VMAT2): Vesicular monoamine transport
• SLC6A2 (NET): Norepinephrine transporter

Normal Function

Cardiovascular Regulation

• ↑ Heart rate (β1 receptors)
• ↑ Myocardial contractility
• ↑ Conduction velocity (AV node)

• Vasoconstriction (α1 receptors)
• Blood pressure maintenance
• Skeletal muscle vasodilation (β2)

Pupillary Control

• Mydriasis: Radial muscle contraction (α1)
• Parasympathetic: Pupillary constriction (muscarinic)
• Clinical: Horner's syndrome (ptosis, miosis, anhidrosis)

Thermoregulation

• Eccrine sweat glands: ACh-mediated secretion (sympathetic)
• Vasoconstriction: Reduce heat loss
• Thermogenic responses: Brown adipose tissue (β3)

Organ Innervation

Stress Response

The sympathetic nervous system mediates the fight-or-flight response:

• Elevated heart rate and blood pressure
• Pupillary dilation
• Bronchodilation
• Mobilization of energy stores
• Decreased non-essential functions

Vulnerability in Disease

Autonomic Neuropathy

• Diabetic autonomic neuropathy: Most common cause of autonomic dysfunction[@freeman2005]
• Cardiovascular dysfunction: Orthostatic hypotension, resting tachycardia
• GI dysfunction: Gastroparesis, constipation
• Sudomotor dysfunction: Anhidrosis, hyperhidrosis

Parkinson's Disease

Sympathetic dysfunction occurs in 50-80% of PD patients:

Multiple System Atrophy

• Severe autonomic failure: More pronounced than in PD
• Sympathetic denervation: Cardiovascular dysfunction
• Peripheral neuropathy: May contribute
• Differentiates from PD: Lack of cardiac sympathetic preservation

Other Disorders

• Pure autonomic failure: Autoimmune/drug-induced
• Autoimmune autonomic ganglionopathy: Anti-ganglionic ACh receptor antibodies
• Chagas disease: Destroy enteric and cardiac sympathetic neurons
• Guillain-Barre syndrome: Autonomic involvement
• Spinal cord injury: Loss of preganglionic neurons

Transcriptomic Profile

Single-cell RNA sequencing of sympathetic neurons:

Enriched Genes

• PHOX2B: Master regulator
• TH, DBH: Catecholamine synthesis
• SLC6A2 (NET): Norepinephrine transporter
• SLC18A2 (VMAT2): Vesicular monoamine transporter
• ADRA1A/D, ADRB1/2/3: Adrenergic receptors
• CNTNAP2: Neuronal adhesion
• NRXN1: Neurexin family

Disease-Relevant Genes

• SNCA: [Alpha-synuclein](/proteins/alpha-synuclein) in sympathetic ganglia (PD)
• [GBA1](/entities/gba): Glucocerebrosidase (PD risk)
• [LRRK2](/entities/lrrk2): Leucine-rich repeat kinase (PD risk)
• PANK2: Coenzyme A synthesis (PKAN)
• MT-ND: Mitochondrial genes (autonomic failure)

Therapeutic Implications

Pharmacological Approaches

Autonomic Dysfunction Management

• Non-pharmacological: Increased salt/fluid intake, compression stockings
• Fludrocortisone: Mineralocorticoid for volume expansion
• Ivabradine: If β-blockers insufficient

Biomarkers

• 123I-MIBG scintigraphy: Cardiac sympathetic innervation
• Heart rate variability: Autonomic tone
• Tilt-table test: Orthostatic intolerance
• Sudomotor testing: Sweat function

Emerging Therapies

• Gene therapy: Restore catecholamine synthesis
• Cell replacement: Sympathetic neuron transplantation
• Immunomodulation: For autoimmune autonomic neuropathy
• Alpha-synuclein targeting: Disease-modifying for PD

Key Publications

Background

The study of Sympathetic Neurons 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.

External Links

• [Autonomic Research Consortium](https://www.arc-neurology.org/)
• [National Dysautonomia Research Foundation](https://www.ndrf.org/)
• [Parkinson's Foundation](https://www.parkinson.org/)parkin)
• [Allen Brain Atlas: Autonomic Ganglia](https://portal.brain-map.org/atlases-and-data/rnaseq)

See Also

• [ad-astrocyte-reactivity-companies](/wiki/companies-ad-astrocyte-reactivity-companies) — contributes_to
• [LRRK2 G2019S Transgenic Mouse Model](/wiki/models-lrrk2-g2019s-transgenic-mouse-model) — causes
• [PSEN2 — Presenilin 2](/wiki/genes-psen2) — expresses
• [WNT3A Gene](/wiki/genes-wnt3a) — activates

Pathway Diagram

The following diagram shows the key molecular relationships involving Sympathetic Neurons discovered through SciDEX knowledge graph analysis: