Cannabis scent compounds ease pain in mouse study
University of Arizona researchers found cannabis terpenes reduced fibromyalgia and post-surgical pain in mice without THC-like intoxication.
By Lucas Ferreira · Science & Environment Writer
3 min read
Compounds that give cannabis and other plants their smell reduced pain in mouse models of fibromyalgia and post-surgical pain, according to University of Arizona Health Sciences researchers. The work matters because the compounds, known as terpenes, are not linked to the psychoactive effects associated with THC, the cannabis ingredient that causes intoxication.
The findings were published in Pharmacological Reports by Caleb A. Seekins, Alyssa M. Welborn, Abigail M. Schwarz and John M. Streicher. The University of Arizona Office of Research and Partnerships said the study extends earlier work from Streicher’s lab showing that terpenes can reduce pain in models of inflammation and chemotherapy-related nerve injury.
Four cannabis terpenes tested
Terpenes are naturally occurring chemicals that help create the scent and taste of many plants, according to the University of Arizona. In cannabis, they are part of the plant’s distinctive aroma and are being studied for possible medical uses.
The Arizona team tested four terpenes found in Cannabis sativa: geraniol, linalool, beta-caryophyllene and alpha-humulene. In mouse models used to study fibromyalgia and post-operative pain, all four compounds produced pain-relieving effects, the researchers reported.
Geraniol showed the strongest effect in the experiments, followed by linalool, beta-caryophyllene and alpha-humulene, according to the university. The researchers said the results do not show terpenes are useful for immediate injury pain, such as a burn or stubbed toe, but do point to possible benefit in chronic or disease-related pain.
Why fibromyalgia is a focus
Fibromyalgia causes widespread pain in muscles and soft tissues and remains difficult to treat, according to the university. Research published in Healthcare (Basel) in 2023 estimated that the condition affects up to 5% of people worldwide.
In the United States, about 4 million adults have fibromyalgia, and women are affected more often than men, according to the U.S. Department of Health and Human Services’ Office on Women’s Health. Streicher, a pharmacology professor at the University of Arizona College of Medicine — Tucson and a member of the Comprehensive Center for Pain & Addiction, said the findings suggest terpenes could become a treatment path for an underserved group of patients.
Possible role after surgery
The study also examined post-surgical pain, which the university described as temporary but biologically different from ordinary acute pain because surgery can trigger inflammation and heightened sensitivity in pain pathways. Streicher said opioids can control post-surgical pain but may cause constipation, which can raise the risk of complications such as adhesions.
Research published in the International Journal of Surgery in 2020 estimated that about 310 million major operations are performed worldwide each year. The Arizona researchers said that scale underscores the need for additional pain-control options.
The team reported that the terpenes appeared to work through adenosine A2a receptors, the same biological pathway identified in earlier terpene studies. Because caffeine blocks that receptor, the researchers said the finding raises questions about whether terpenes may also have sedative effects that need further study.
Todd Vanderah, director of the Comprehensive Center for Pain & Addiction at U of A Health Sciences and head of pharmacology at the College of Medicine — Tucson, said the work shows why researchers continue to study chemicals made by plants and animals. The National Institutes of Health funded the research under award R01AT011517, according to the university.
This story draws on original reporting from ScienceDaily.