ArticleInvestigative ophthalmology & visual science2020
THC Regulates Tearing via Cannabinoid CB1 Receptors.
Article in Investigative ophthalmology & visual science, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 16 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
16 citing papers in PubMed, 1 synthesis or guideline pooled it, 21 citations in OpenAlex.
- TFOS lifestyle: Impact of societal challenges on the ocular surface.The ocular surface · 2023Pooled it
- N-Arachidonoyl-phosphatidylethanolamide phospholipase D activation by muscarinic receptors.The Journal of physiology · 2026Article
- Drug-laced vaping-implications and emerging perioperative challenges for the anesthesiologist: a narrative review.Canadian journal of anaesthesia = Journal canadien d'anesthesie · 2026Review
- Short-Term Daily Oral Administration of Cannabidiol Does Not Impact Rebound Tonometry Intraocular Pressure or Schirmer Tear Test Values in Healthy Adult Horses.Veterinary ophthalmology · 2026Article
- Don't Sweat It: Cannabinoid CB1 Receptors Reduce Sweating in a Mouse Model.FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2026Article
- Cannabinoid Regulation of Murine Vaginal Secretion.Biomolecules · 2025Article
- A Sex-Dependent Cannabinoid CB1 Receptor Role in Circadian Tearing of the Mouse.Investigative ophthalmology & visual science · 2024Article
- Murine vaginal secretory responses to a male volatile chemical messenger.Scientific reports · 2024Article
- Cannabinoid regulation of sex-dependent murine odorant-stimulated salivation.Scientific reports · 2024Article
- Tear film assessment before and after phacoemulsification in patients with age-related cataracts.BMC ophthalmology · 2024Observational
- Adverse Ocular Impact and Emerging Therapeutic Potential of Cannabis and Cannabinoids: A Narrative Review.Clinical ophthalmology (Auckland, N.Z.) · 2024Review
- Article
- Cannabinoid-Based Ocular Therapies and Formulations.Pharmaceutics · 2023Review
- Cannabinoid CB1 receptors regulate salivation.Scientific reports · 2022Article
- Considerations for Cannabinoids in Perioperative Care by Anesthesiologists.Journal of clinical medicine · 2022Review
- Spatial transcriptomics of the lacrimal gland features macrophage activity and epithelium metabolism as key alterations during chronic inflammation.Frontiers in immunology · 2022Article
Corrections and comments
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Authors and funding
6 authors at 2 institutions in 1 country.
Funding
Abstract
Purpose: Aqueous deficiency dry eye (ADDE) is a chronic condition affecting millions, with symptoms ranging from a dry itchiness to blurred vision and accompanied by an increased risk of eye infections. ADDE typically arises from disorders of the lacrimal gland that produces tears necessary for eye lubrication. Cannabis users frequently report dry eye, but the basis for this is unknown. If the effects occur via the endogenous cannabinoid signaling system, then this may represent a novel mechanism for the regulation of tearing. Methods: We examined expression of cannabinoid CB1 receptors in the lacrimal gland using immunohistochemistry, Western blotting, and PCR and tested tetrahydrocannabinol (THC) regulation of tearing in wild-type and CB1-null mice. Results: We now report that CB1 receptors are expressed in the axons of cholinergic neurons innervating the lacrimal gland. Little if any staining is seen in lacrimal gland epithelial cells (acinar and ductal) or myoepithelial cells (MECs). Activation of CB1 receptors by THC or the cannabinoid agonist CP55940 reduces tearing in male mice. In female mice, THC has no effect, but CP55940 increases tearing. In both sexes, the effect of CP55940 is absent in CB1 knockout mice. CB1 mRNA and protein levels are approximately four- to fivefold higher in males than females. In male knockouts, THC increases tearing, suggesting that THC also acts through different receptors. Conclusions: Our results suggest a novel, albeit sex-dependent, physiologic basis for the dry eye symptoms experienced by cannabis users: activation of neuronal CB1 receptors in the lacrimal gland reduces tearing.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.