Lung and the endocannabinoid system
Airway nerves and bronchi.
Airway nerves and bronchi. 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.
ChestCB1 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.
Lung: RNA level of the receptor gene in human tissue (tissue consensus data). Across lung tissue as a whole, CB1 RNA is low; CB2 is very low. Human Protein AtlasHuman tissue
| Receptor | Gene | RNA (nTPM) | Level |
|---|---|---|---|
| CB1 | CNR1 | 2.8 | low |
| CB2 | CNR2 | 0.1 | very low |
What does it do there?
Across lung tissue as a whole, CB1 receptor RNA is measured at low levels, but the receptor works at specific points in the airways. In the lab, in bronchial segments taken from 88 people, some cannabinoids reduced nerve-triggered bronchial contraction through CB1; the receptor was not on the muscle itself but on the ending of the nerve that reaches it. In guinea pigs and rats, the body's own cannabinoid anandamide was made in lung tissue and tuned the response of the bronchi in two directions through CB1 on the endings of airway nerves. Human Protein AtlasHuman tissueGrassin-Delyle 2014Human tissueCalignano 2000AnimalVizi 2001Animal
CB1, CB2 and TRPV1 receptors have been shown in the cells lining the inner surface of the airways (the epithelium). Immune cells that reside in the lung (macrophages) both make endocannabinoids and carry CB1 and CB2. Fantauzzi 2020Human tissueGkoumassi 2007Cell / labStaiano 2016Human tissueCell / lab
Student level: terms and cell types
In human bronchi (organ bath), Δ9-THC, WIN55,212-2 and CP55,940 inhibited cholinergic contraction evoked by electrical field stimulation in a concentration-dependent manner, by up to 39%, 76% and 77%, respectively; 2-AG and the GPR55 agonist O-1602 were ineffective. The effect was blocked by the CB1 antagonist SR141716 but not by a CB2 antagonist; contraction to exogenous acetylcholine was unchanged, meaning the response goes through prejunctional CB1. In rodents, anandamide inhibited capsaicin-evoked bronchospasm and cough through CB1 on axon terminals, but caused bronchospasm when vagal tone was removed. In guinea pig lung, CB1 was on neuropeptide Y–positive noradrenergic terminals and reduced noradrenaline release. Human Protein AtlasHuman tissueGrassin-Delyle 2014Human tissueCalignano 2000AnimalVizi 2001Animal
CB1, CB2 and TRPV1 protein were detected in human airway epithelium, both in tissue and in culture. In a human bronchial epithelial cell line, CB2 inhibited adenylyl cyclase and reduced TNF-α–induced IL-8 release. Human lung macrophages produced 2-AG, anandamide, PEA and OEA, and selectively synthesized 2-AG when stimulated with LPS; they carried CB1 and CB2, and selective agonists inhibited LPS-induced release of VEGF-A, VEGF-C and angiopoietins. Fantauzzi 2020Human tissueGkoumassi 2007Cell / labStaiano 2016Human tissueCell / lab
Expert level: method notes and numbers
Lung: RNA level of the receptor gene in human tissue (tissue consensus data). Across lung tissue as a whole, CB1 RNA is low; CB2 is very low. Human Protein AtlasHuman tissue
Method note
Grassin-Delyle 2014: isolated human bronchi from 88 people, organ bath, cholinergic contraction by EFS; diagnoses not given in the abstract. Calignano 2000: guinea pigs and rats; anandamide synthesis in lung tissue in response to Ca²⁺ stimulation. Vizi 2001: guinea pig lung, [³H]noradrenaline release, WIN-55,212-2 IC50 41.5 nM (1 Hz). Grassin-Delyle 2014Human tissueCalignano 2000AnimalVizi 2001Animal
Fantauzzi 2020: 1,090 bronchial brushing gene expression profiles (healthy and diseased), immunohistochemistry and immunoblot (disease findings are not used here). Gkoumassi 2007: 16HBE14o− cell line. Staiano 2016: human lung-resident macrophages, LPS stimulation; sample size not given in the abstract. Fantauzzi 2020Human tissueGkoumassi 2007Cell / labStaiano 2016Human tissueCell / lab
What is known about CBD?
In the lab, in guinea pig bronchial segments, CBD did not change the contraction caused by some contracting agents, but it reduced the responses caused by anandamide and virodhamine. In another cell study, cell lines derived from the airways did not break down CBD; only liver-derived cells converted CBD into its metabolites. These are laboratory findings. Dudášová 2013AnimalTongkanarak 2025Cell / labComputer model
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 | 2.8 | cerebral cortex (18.6) |
| CB2 CNR2 | Cannabinoid receptor | 0.1 | spleen (8.4) |
| TRPV1 | Heat and chili pepper sensor · ion channel | 2.8 | liver (21.8) |
| GPR55 | Long an "orphan" receptor · in the cell membrane | 0.4 | testis (4.4) |
| PPARγ PPARG | Gene switch · in the cell nucleus | 26.7 | adipose tissue (153.2) |
| 5-HT1A HTR1A | Serotonin receptor · in the cell membrane | 0.0 | hippocampal formation (6.1) |
| TRPV2 | Relative of TRPV1 · ion channel | 29.5 | lung (29.5) |
| Endocannabinoid enzymes | |||
| NAPE-PLD NAPEPLD | Makes anandamide | 2.8 | kidney (13.9) |
| FAAH | Breaks down anandamide | 7.5 | testis (46.0) |
| DAGLα DAGLA | Makes 2-AG | 1.5 | cerebral cortex (12.3) |
| DAGLβ DAGLB | Makes 2-AG | 8.8 | adrenal gland (15.2) |
| MGL MGLL | Breaks down 2-AG | 67.2 | adipose tissue (161.3) |
| ABHD6 | Breaks down 2-AG | 8.0 | liver (60.7) |
| ABHD12 | Breaks down 2-AG | 30.7 | 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 | 0.1 | 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
- Lung
- Lung · MeSH D008168 · UBERON 0002048 · Wikidata Q7886
- Receptors
- CB1 (CNR1, UniProt P21554) · CB2 (CNR2, UniProt P34972)
How to cite: cbd.school editorial team. Lung and the endocannabinoid system. Endocannabinoid system 3D map, cbd.school. Last updated October 24, 2026. https://cbd.school/learn/endocannabinoid-system-map/akciger/
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 10 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
- Grassin-Delyle S, Naline E, Buenestado A et al. Cannabinoids inhibit cholinergic contraction in human airways through prejunctional CB1 receptors. Br J Pharmacol. 2014;171(11):2767-77. PMID 24467410 · doi:10.1111/bph.12597 Human tissue
- Calignano A, Kátona I, Désarnaud F et al. Bidirectional control of airway responsiveness by endogenous cannabinoids. Nature. 2000;408(6808):96-101. PMID 11081515 · doi:10.1038/35040576 Animal
- Vizi ES, Katona I, Freund TF. Evidence for presynaptic cannabinoid CB(1) receptor-mediated inhibition of noradrenaline release in the guinea pig lung. Eur J Pharmacol. 2001;431(2):237-44. PMID 11728431 · doi:10.1016/s0014-2999(01)01413-3 Animal
- Fantauzzi MF, Aguiar JA, Tremblay BJ et al. Expression of endocannabinoid system components in human airway epithelial cells: impact of sex and chronic respiratory disease status. ERJ Open Res. 2020;6(4):00128-2020. PMID 33344628 · doi:10.1183/23120541.00128-2020 Human tissue
- Gkoumassi E, Dekkers BG, Dröge MJ et al. Virodhamine and CP55,940 modulate cAMP production and IL-8 release in human bronchial epithelial cells. Br J Pharmacol. 2007;151(7):1041-8. PMID 17558435 · doi:10.1038/sj.bjp.0707320 Cell / lab
- Staiano RI, Loffredo S, Borriello F et al. Human lung-resident macrophages express CB1 and CB2 receptors whose activation inhibits the release of angiogenic and lymphangiogenic factors. J Leukoc Biol. 2016;99(4):531-40. PMID 26467187 · doi:10.1189/jlb.3HI1214-584R Human tissueCell / lab
- Dudášová A, Keir SD, Parsons ME et al. The effects of cannabidiol on the antigen-induced contraction of airways smooth muscle in the guinea-pig. Pulm Pharmacol Ther. 2013;26(3):373-9. PMID 23428645 · doi:10.1016/j.pupt.2013.02.002 Animal
- Tongkanarak K, Paul PK, Bintang MAKM et al. Metabolism of Cannabidiol in Respiratory-Associated Cells and HepG2-Derived Cells and Molecular Docking of Cannabidiol and Its Metabolites with CYP Enzymes and Cannabinoid Receptors. Int J Mol Sci. 2025;26(17):8384. PMID 40943305 · doi:10.3390/ijms26178384 Cell / labComputer model
- 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