Arcuate Nucleus (ARC) Expanded

Introduction

Arcuate Nucleus (ARC) Expanded
**Category**	Hypothalamus / Neuroendocrine
**Location**	Mediobasal hypothalamus, adjacent to median eminence
**Function**	Energy homeostasis, appetite regulation, neuroendocrine control
**Diseases**	Alzheimer's Disease, Parkinson's Disease, Huntington's Disease, Metabolic Disorders
Database	ID
Cell Ontology	[CL:1001135](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_1001135)
Cell Ontology	[CL:1001142](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_1001142)
Cell Ontology	[CL:1001213](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_1001213)
Taxonomy	ID
Cell Ontology (CL)	[CL:1001135](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_1001135)

Arcuate Nucleus (Arc) Expanded 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 Arcuate Nucleus (also known as the infundibular nucleus) is a major hypothalamic nucleus located in the mediobasal hypothalamus, adjacent to the third ventricle. It plays critical roles in energy homeostasis, neuroendocrine regulation, and is importantly involved in neurodegenerative diseases.

Overview

Taxonomy & Classification

External Database Links

• Cell Ontology (CL:1001135)

• OBO Foundry (CL:1001135)

• Allen Brain Cell Atlas

• CellxGene Census

Multi-Taxonomy Classification

Taxonomy Database Cross-References

External Database Links

• Cell Ontology (CL:1001135)

• OBO Foundry (CL:1001135)

• Allen Brain Cell Atlas

• CellxGene Census

• Human Cell Atlas

Structure

The arcuate nucleus is a paired structure located at the base of the hypothalamus. It contains multiple neuronal populations:

Key Neuron Populations

NPY/AgRP Neurons

• Co-express neuropeptide Y (NPY) and agouti-related peptide (AgRP)

• Potent orexigenic (appetite-stimulating) neurons

• Activation drives feeding behavior

• Express leptin receptors

POMC Neurons

• Express proopiomelanocortin (POMC) α-M- ProduceSH (melanocortin)

• Anorexigenic (appetite-suppressing)

• Respond to leptin and ghrelin

GABAergic Neurons

• Provide inhibitory signals

• Modulate POMC neuron activity

• Connect to reward pathways

Dopaminergic Neurons

• Project to median eminence

• Regulate prolactin secretion

• Affected in Parkinson’s disease

Function

Energy Homeostasis

• Integrates hormonal signals (leptin, ghrelin, insulin)

• Regulates food intake and energy expenditure

• Controls body weight

• Responds to metabolic state

Neuroendocrine Regulation

• Controls pituitary hormone secretion

• Regulates growth hormone axis

• Modulates stress response

• Controls reproduction

Autonomic Integration

• Projects to brainstem autonomic centers

• Modulates vagal activity

• Connects to limbic system

Disease Relevance

Alzheimer’s Disease

• Metabolic dysfunction in AD brain

• Type 3 diabetes hypothesis links to hypothalamic dysfunction

• Early hypothalamic atrophy in AD

• Leptin signaling alterations

• Appetite and weight loss in later stages

Parkinson’s Disease

• Hypothalamic dysfunction contributes to non-motor symptoms

• Sleep disorders linked to hypothalamic changes

• Autonomic dysfunction involves hypothalamic pathways

• Weight changes common in PD

Huntington’s Disease

• Hypothalamic involvement early in disease

• Sleep and circadian disturbances

• Metabolic changes

• Weight loss and cachexia

Metabolic Disorders

• Obesity associated with arcuate dysfunction

• Leptin resistance

• Ghrelin signaling alterations

• Insulin resistance

Molecular Markers

• NPY: Neuropeptide Y

• AgRP: Agouti-related peptide

• POMC: Proopiomelanocortin

• α-MSH: Alpha-melanocyte stimulating hormone

• LEPR: Leptin receptor

• GHSR: Ghrelin receptor

• TH: Tyrosine hydroxylase (dopaminergic neurons)

Therapeutic Implications

Pharmacological

• Melanocortin receptor agonists/antagonists

• NPY receptor ligands

• Leptin therapy (for rare mutations)

• Ghrelin modulators

Lifestyle Interventions

• Calorie restriction

• Intermittent fasting

• Exercise

• Sleep optimization

Research Directions

• Hypothalamic stem cell transplantation

• Gene therapy for leptin signaling

• Metabolic interventions for neurodegeneration

Background

The study of Arcuate Nucleus (Arc) Expanded 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.