GAL Gene
Introduction
Gal Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
<div class="infobox infobox-gene"> [@crawley2018]
<div class="infobox-header">GAL</div> [@liu2019]
<div class="infobox-row"><strong>Full Name:</strong> Galanin</div> [@counts2008]
<div class="infobox-row"><strong>Chromosome:</strong> 11q13.2</div> [@holmes2008]
<div class="infobox-row"><strong>NCBI Gene ID:</strong> [6447](https://www.ncbi.nlm.nih.gov/gene/6447)</div> [@lang2022]
<div class="infobox-row"><strong>Ensembl ID:</strong> [ENSG00000178394](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000178394)</div> [@mazarati2018]
<div class="infobox-row"><strong>OMIM:</strong> [137035](https://www.omim.org/entry/137035)</div> [@kuteeva2008]
<div class="infobox-row"><strong>UniProt:</strong> [P60880](https://www.uniprot.org/uniprot/P60880)</div>
<div class="infobox-row"><strong>Associated Diseases:</strong> [Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), Depression, Epilepsy, Pain Disorders</div>
<div class="infobox-row"><strong>Protein Class:</strong> Neuropeptide, GPCR ligand</div>
<div class="infobox-row"><strong>Brain Expression:</strong> High in hypothalamus, amygdala, hippocampus, dorsal raphe</div>
</div>
Pathway Diagram
Mermaid diagram (expand to render)
Knowledge graph relationships for GAL (282 total edges in KG)
Overview
Galanin is a 30-amino acid neuropeptide encoded by the GAL gene on chromosome 11q13.2 that acts as a widespread neuromodulator in the central and peripheral nervous systems[@tatemoto1983]. Galanin is unique among neuropeptides in its ability to co-exist with classical neurotransmitters, particularly [acetylcholine](/entities/acetylcholine) and norepinephrine, allowing it to fine-tune neuronal circuits involved in cognition, mood, pain processing, and neuroprotection.
Normal Function
The GAL gene encodes preprogalanin, which is processed to galanin (1-29) and galanin message-associated peptide (GMAP). Galanin is widely distributed in the brain and peripheral tissues[@crawley2018].
Neuromodulation
- Co-released with acetylcholine in basal forebrain
- Modulates norepinephrine in locus coeruleus
- Inhibits glutamate release
- Reduces GABAergic transmission
Cognitive Functions
- Influences learning and memory
- Modulates hippocampal synaptic plasticity
- Role in attention and arousal
Pain and Sensory Processing
- Involved in pain transmission and modulation
- Alters nociceptive processing
- Effects in spinal cord dorsal horn
Energy Homeostasis
- Regulates food intake
- Modulates energy expenditure
- Interactions with orexigenic pathways
Expression Pattern
Galanin shows widespread expression:
| Brain Region | Expression Level | Functional Significance |
|--------------|------------------|------------------------|
| Hypothalamus | Very High | Energy homeostasis |
| Hippocampus | High | Memory, plasticity |
| Amygdala | High | Emotional processing |
| Dorsal Raphe | High | Mood, serotonin interaction |
| Locus Coeruleus | High | Arousal, attention |
| Spinal Cord | High | Pain modulation |
| [Cortex](/brain-regions/cortex) | Moderate | Cognition |
Molecular Mechanisms
Galanin signals through three G-protein coupled receptors (GALR1, GALR2, GALR3), each with unique signaling properties[@liu2019]:
Receptor Signaling Pathways
- GALR1: Gi/o-coupled, inhibits cAMP, hyperpolarizes [neurons](/entities/neurons)
- GALR2: Gq/11-coupled, activates PLC, increases intracellular calcium
- GALR3: Gi/o-coupled, similar to GALR1
Intracellular Signaling
- Inhibition of adenylate cyclase
- Activation of phospholipase C
- Modulation of potassium channels
- MAPK pathway activation
Disease Associations
Alzheimer's Disease
Galanin is upregulated in AD brains, particularly in the basal forebrain[@counts2008]. This upregulation may represent a compensatory neuroprotective response or contribute to cholinergic dysfunction. Galaninergic drugs are being explored for cognitive enhancement.
Parkinson's Disease
Galanin co-localizes with dopaminergic neurons and may modulate their function. Changes in galanin expression are observed in PD brains, potentially affecting motor and non-motor symptoms.
Depression
Galanin signaling is implicated in mood disorders. GALR3 antagonists show potential antidepressant effects in preclinical models.
Epilepsy
Galanin has anticonvulsant properties through inhibition of excitatory neurotransmission. Galanin agonists may have therapeutic potential.
Pain Disorders
Galanin modulates pain transmission in the spinal cord. The peptide has both pro-nociceptive and anti-nociceptive effects depending on receptor subtype and location.
Therapeutic Implications
Galanin Receptor Ligands
| Drug/Compound | Target | Development Stage | Application |
|--------------|--------|------------------|-------------|
| Galanin agonists | GALR1/2 | Research | Epilepsy, analgesia |
| Galanin antagonists | GALR3 | Preclinical | Depression, anxiety |
| Galnon | GALR1/2 agonist | Research | Cognitive enhancement |
| M617 | GALR1 agonist | Research | Pain, cognition |
Potential Applications
- Cognitive enhancement in AD
- Mood regulation
- Anticonvulsant therapy
- Pain management
Research Directions
Receptor Subtype Selectivity: Developing selective ligands
Neuroprotection: Understanding galanin's neuroprotective mechanisms
Cognitive Enhancement: Galanin as cognitive enhancer
Pain Modulation: Therapeutic pain applications
Mood Disorders: Depression and anxiety treatmentAnimal Models
Knockout Mice
- GALR1 knockout: increased anxiety, seizures
- GALR2 knockout: impaired nerve regeneration
- GALR3 knockout: altered stress response
Transgenic Models
- Galanin overexpression: neuroprotection
- Galanin depletion: cognitive deficits
Clinical Relevance
Galanin system modulation offers potential for:
- Neurodegeneration: Cognitive enhancement in AD
- Psychiatric: Depression, anxiety treatment
- Neurology: Anticonvulsant effects
- Pain: Analgesic or algesic modulation
See Also
- [Genes Index](/genes)
- [Proteins Index](/proteins)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Hypothalamus](/brain-regions/hypothalamus)
- [Hippocampus](/brain-regions/hippocampus)
- [Amygdala](/cell-types/basolateral-amygdala)
External Links
- [NCBI Gene: GAL](https://www.ncbi.nlm.nih.gov/gene/6447)
- [UniProt: Galanin](https://www.uniprot.org/uniprot/P60880)
- [Ensembl: GAL](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000178394)
Background
The study of Gal Gene 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.
Allen Brain Atlas Resources
The Allen Brain Atlas provides comprehensive gene expression data across brain regions and cell types.
- [Allen Human Brain Atlas](https://human.brain-map.org/) — Gene expression data across the adult human brain
- [Allen Mouse Brain Atlas](https://mouse.brain-map.org/) — Gene expression in mouse brain
- [Allen Cell Type Atlas](https://celltypes.brain-map.org/) — Single-cell transcriptomics data
- [Allen Brain Map Portal](https://portal.brain-map.org/) — Access to all Allen Institute brain data
Search for expression data on the Allen Brain Atlas:
- [Human Brain Atlas search for GAL](https://human.brain-map.org/microarray/search/show?search_term=GAL)
- [Mouse Brain Atlas search for GAL](https://mouse.brain-map.org/search/index.html?query=GAL)
References
[Tatemoto K, Rökaeus A, Jörnvall H, McDonald TJ, Mutt V, Galanin - a novel biologically active peptide from porcine intestine (1983)](https://pubmed.ncbi.nlm.nih.gov/6198235/)
[Crawley JN, Galanin impairs cognitive abilities in rodents: relevance to Alzheimer's disease (2018)](https://pubmed.ncbi.nlm.nih.gov/30341625/)
[Unknown, Liu HX, Hökfelt T. The galaninergic system in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31295584/)
[Counts SE, Perez SE, Kahl J, et al, Galanin in Alzheimer disease (2008)](https://pubmed.ncbi.nlm.nih.gov/18332267/)
[Holmes A, Kinney JW, Wrenn CC, et al, Galanin transgenic mice: galanin and behavior (2008)](https://pubmed.ncbi.nlm.nih.gov/18500646/)
[Lang R, Gundlach AL, Kofler B, The galanin peptide family: receptor signaling, neurofunctions, and therapeutic approaches (2022)](https://pubmed.ncbi.nlm.nih.gov/34606821/)
[Unknown, Mazarati A, Langel U, Hökfelt T. Galanin and epilepsy (2018)](https://pubmed.ncbi.nlm.nih.gov/29500593/)
[Kuteeva E, Hökfelt T, Wardi T, Ogren SO, Galanin, galanin receptor subtypes and depression-like behaviour (2008)](https://pubmed.ncbi.nlm.nih.gov/18555279/)Pathway Diagram
The following diagram shows the key molecular relationships involving GAL Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)