Spinal cord and nerves: the endocannabinoid system
The gateway for pain signals.
The gateway for pain signals. Where the cannabinoid receptors CB1 and CB2 sit in this region, what they do there, and what is actually known about CBD; at three levels for Everyone, Students and Experts, with sources.
Nerves and sensesCB1 low · CB2 very low (Human Protein Atlas)Last updated:
What's on this page?
Interactive 3D · real anatomy and real data
Where in your body are the cannabinoid receptors?
About 1.4 MB to download.
Regions
How to read it Choose a region, or tap a glowing point on the map.
- Solid light is the CB1 receptor, a ring is CB2. Each region has its own color; the color only tells regions apart.
- The strength of the light is the receptor gene level measured in human tissue (Human Protein Atlas). That is why the liver’s point is dim: a healthy liver has few receptors.
- With the layer selector above you can also see other receptors, the enzymes that make and break down endocannabinoids, and the liver enzymes that break down CBD and THC.
- Every piece of information shows its source and the type of evidence (human, animal, cell). You can change the reading level above.
- Drag to rotate. Use the + and − buttons to zoom; on a computer, Ctrl or ⌘ with the scroll wheel, on a phone, two fingers.
Spinal cord: RNA level of the receptor gene in human tissue (tissue consensus data). In the tissue consensus data, this is the average for the whole spinal cord tissue; in animal studies, the receptor is concentrated at the surface of the dorsal horn. Human Protein AtlasHuman tissue
| Receptor | Gene | RNA (nTPM) | Level |
|---|---|---|---|
| CB1 | CNR1 | 1.7 | low |
| CB2 | CNR2 | 0 | very low |
What does it do there?
In the rat spinal cord, CB1 was seen mostly in the surface layers of the dorsal horn, where pain signals are first processed; most of it was in the interneurons there. Some of the nerve cells that carry sensory signals to the spinal cord also make CB1; these are mostly medium-sized and large cells. Farquhar-Smith 2000AnimalHohmann and Herkenham 1999Animal
The endocannabinoid system is considered one of the body's own pain control systems; most of this knowledge comes from animal studies. Woodhams 2017Review
This distribution is similar in humans: in spinal cord tissue taken from organ donors, CB1 was clearly denser in the surface layers of the dorsal horn, where pain signals are processed, than in the deeper layers; there was no difference between women and men. Parnell 2023Human tissueAnimal
Student level: terms and cell types
In the rat spinal cord, CB1 immunoreactivity was found in the dorsolateral funiculus, in the superficial dorsal horn (a double band at lamina I and at the inner lamina II / III transition) and in lamina X. Although it lay in the same laminae as primary afferent nociceptor markers, co-staining at the axon level was limited; co-staining with interneurons carrying protein kinase C γ suggests that most of the expression is in spinal interneurons. In the dorsal root ganglion, CB1 mRNA was mainly in medium- and large-diameter cells; only 13% of cells with substance P mRNA and 10% of cells with α-CGRP carried CB1 mRNA. Farquhar-Smith 2000AnimalHohmann and Herkenham 1999Animal
According to a review, the endocannabinoid system is an intrinsic pain control system involved in the sensory, emotional and cognitive aspects of pain. The review's data come mostly from preclinical (animal) studies; it also discusses the clinical failures of endocannabinoid-related treatments in recent years. Woodhams 2017Review
In rat and human spinal cord (organ donors; 7 women, 7 men), immunohistochemistry and confocal imaging showed CB1 immunoreactivity to be significantly higher in the superficial dorsal horn (the CGRP-positive region) than in the deep dorsal horn (P = 0.018 in both sexes); values in the superficial horn did not differ by species or sex. CB1 was mainly in the neuropil and in dorsal horn neurons rather than in peptidergic afferents; in single-cell/single-nucleus RNA sequencing data, CNR1 was prominent in rodent and human dorsal horn neuron subgroups, but CNR2 was not. Parnell 2023Human tissueAnimal
Expert level: method notes and numbers
Spinal cord: RNA level of the receptor gene in human tissue (tissue consensus data). In the tissue consensus data, this is the average for the whole spinal cord tissue; in animal studies, the receptor is concentrated at the surface of the dorsal horn. In the HPA brain region data (spinal cord), CB1 is 9.8 nTPM; the two datasets come from different samples and methods, so their numbers cannot be converted into each other directly. Human Protein AtlasHuman tissue
Method note
Farquhar-Smith 2000: immunocytochemistry and western blot in the spinal cord of male and female Wistar rats; source separation by dorsal rhizotomy and rostral hemisection (only small changes). No quantitative density value in the abstract. Farquhar-Smith 2000Animal
Hohmann and Herkenham 1999: double-label in situ hybridization in rat dorsal root ganglia (35S riboprobe for CB1, digoxigenin for neuropeptides); CB1 mRNA in fewer than 0.5% of somatostatin cells. According to the authors, these cells may transport the receptor to their terminals in the superficial dorsal horn. Hohmann and Herkenham 1999Animal
The spinal cord (white matter and dorsal horn), dorsal root ganglia and main peripheral nerves come from the Z-Anatomy model. The flowing lights in the nerves and spinal cord are illustrative, not measurements.
What is known about CBD?
No effect found Moderate evidence
In the guide: Chronic Pain and CBD
Research has not found that CBD helps with this condition. If you are considering CBD, you can talk with your doctor or pharmacist, including about the medicines you take.
Mixed results Weak evidence
In the guide: Neuropathic Pain and CBD
Research results are mixed. It has not been proven that CBD works for this condition. If you are considering CBD, you can talk with your doctor or pharmacist, including about the medicines you take.
Not studied enough Insufficient evidence
In the guide: Spasticity Other Than MS and CBD
There is not enough research in humans. It is not known whether CBD works. If you are considering CBD, you can talk with your doctor or pharmacist, including about the medicines you take.
Which receptor and enzyme genes are read in this region?
Values in this region for the genes in the map's layer selector: besides CB1 and CB2, the other targets of cannabinoids, the enzymes that make and break down endocannabinoids, and the liver enzymes that break down CBD and THC.
| Gene | What does it do? | Here | Tissue where it is read the most |
|---|---|---|---|
| Receptors | |||
| CB1 CNR1 | Cannabinoid receptor | 1.7 | cerebral cortex (18.6) |
| CB2 CNR2 | Cannabinoid receptor | 0.0 | spleen (8.4) |
| TRPV1 | Heat and chili pepper sensor · ion channel | 6.4 | liver (21.8) |
| GPR55 | Long an "orphan" receptor · in the cell membrane | 0.1 | testis (4.4) |
| PPARγ PPARG | Gene switch · in the cell nucleus | 2.2 | adipose tissue (153.2) |
| 5-HT1A HTR1A | Serotonin receptor · in the cell membrane | 0.3 | hippocampal formation (6.1) |
| TRPV2 | Relative of TRPV1 · ion channel | 3.7 | lung (29.5) |
| Endocannabinoid enzymes | |||
| NAPE-PLD NAPEPLD | Makes anandamide | 3.2 | kidney (13.9) |
| FAAH | Breaks down anandamide | 43.2 | testis (46.0) |
| DAGLα DAGLA | Makes 2-AG | 0.7 | cerebral cortex (12.3) |
| DAGLβ DAGLB | Makes 2-AG | 6.3 | adrenal gland (15.2) |
| MGL MGLL | Breaks down 2-AG | 36.4 | adipose tissue (161.3) |
| ABHD6 | Breaks down 2-AG | 36.2 | liver (60.7) |
| ABHD12 | Breaks down 2-AG | 113.9 | epididymis (125.2) |
| Enzymes that break down CBD and THC | |||
| CYP3A4 | Breaks down CBD and THC | 0.0 | liver (3,367.1) |
| CYP2C19 | Breaks down CBD | 0.0 | liver (178.0) |
| CYP2C9 | Breaks down THC | 0.0 | liver (1,607.6) |
RNA level shows how much the gene is read in this tissue; it does not directly show the amount of protein or how active an enzyme is. Human Protein Atlas (layers)Human tissue
Identifiers and citation
- Spinal Cord
- Spinal Cord · MeSH D013116 · UBERON 0002240 · Wikidata Q9606
- Peripheral Nerves
- Peripheral Nerves · MeSH D010525 · UBERON 0001021 · Wikidata Q11519747
- Receptors
- CB1 (CNR1, UniProt P21554) · CB2 (CNR2, UniProt P34972)
How to cite: cbd.school editorial team. Spinal cord and nerves: the endocannabinoid system. Endocannabinoid system 3D map, cbd.school. Last updated October 24, 2026. https://cbd.school/learn/endocannabinoid-system-map/omurilik/
The body model is derived from BodyParts3D (DBCLS, CC BY 4.0) and Z-Anatomy (CC BY-SA 4.0); receptor levels from Human Protein Atlas v25 (CC BY 4.0). The map, text and downloaded images are CC BY-SA 4.0. An independent expert review has not been done yet. All licenses
Other pages of the map
Overview: what the endocannabinoid system is, the feedback brake at the synapse, CBD's targets, lesson mode, data and licenses.
Sources
Show 6 references
- Human Protein Atlas v25: tissue RNA consensus data (rna_tissue_consensus.tsv, HPA and GTEx, nTPM) and brain region data (rna_brain_region_hpa.tsv, nTPM), CNR1 (ENSG00000118432) and CNR2 (ENSG00000188822); v25.proteinatlas.org, file date November 6, 2025, downloaded October 24, 2026. Uhlén M et al. Tissue-based map of the human proteome. Science. 2015;347(6220):1260419. License CC BY 4.0. PMID 25613900 · doi:10.1126/science.1260419 Human tissue
- Farquhar-Smith WP, Egertová M, Bradbury EJ et al. Cannabinoid CB(1) receptor expression in rat spinal cord. Mol Cell Neurosci. 2000;15(6):510-21. PMID 10860578 · doi:10.1006/mcne.2000.0844 Animal
- Hohmann AG, Herkenham M. Localization of central cannabinoid CB1 receptor messenger RNA in neuronal subpopulations of rat dorsal root ganglia: a double-label in situ hybridization study. Neuroscience. 1999;90(3):923-31. PMID 10218792 · doi:10.1016/s0306-4522(98)00524-7 Animal
- Woodhams SG, Chapman V, Finn DP, Hohmann AG, Neugebauer V. The cannabinoid system and pain. Neuropharmacology. 2017;124:105-120. PMID 28625720 · doi:10.1016/j.neuropharm.2017.06.015 Review
- Parnell J, Martin N, Dedek A et al. Cannabinoid CB1 Receptor Expression and Localization in the Dorsal Horn of Male and Female Rat and Human Spinal Cord. Can J Pain. 2023;7(2):2264895. PMID 38170158 · doi:10.1080/24740527.2023.2264895 Human tissueAnimal
- Human Protein Atlas v25: tissue RNA consensus data (rna_tissue_consensus.tsv, HPA and GTEx, nTPM), the 17 genes in the map's layer selector: CNR1, CNR2, TRPV1, GPR55, PPARG, HTR1A, TRPV2, NAPEPLD, FAAH, DAGLA, DAGLB, MGLL, ABHD6, ABHD12, CYP3A4, CYP2C19, CYP2C9; v25.proteinatlas.org/download/tsv/rna_tissue_consensus.tsv.zip, downloaded October 24, 2026. Uhlén M et al. Tissue-based map of the human proteome. Science. 2015;347(6220):1260419. License CC BY 4.0. PMID 25613900 · doi:10.1126/science.1260419 Human tissue