Voluntary Cannabinoid Gelatin in Mice Produced Different Pain-Outcome Patterns
Voluntary consumption is a useful experimental feature, but it does not make a mouse treatment study equivalent to human edible use. A gelatin-administration model found sustained cannabinoid effects on some nerve-injury outcomes, with important differences among measurements.
Mice chose when to consume
Male and female mice consumed gelatin containing THC, CBD or morphine over several weeks. Investigators recorded consumption and detected drug exposure in serum. THC-gelatin consumption was lower than consumption in the other reported drug-gelatin groups.
The pain-related outcomes were not identical
All three treatments reduced measures of allodynia in the nerve-injury model. The abstract reports tolerance to morphine after a week, whereas THC and CBD retained effects on allodynia over three weeks. At the final hyperalgesia assessment, THC showed a significant effect, CBD a trend and morphine no effect.
A trend is not the same as a significant result
The different hyperalgesia findings should remain separate from the allodynia results. The investigators also recorded ultrasonic clicks associated with injury that decreased with treatment, proposing another potential research measure. Those vocalizations are not direct human pain ratings.
Self-directed intake introduces a different exposure pattern from fixed injections and complicates simple dose comparisons. Serum detection supports exposure, not proof of impairment or equivalence among treatments. The study offers a way to investigate repeated oral administration in mice without establishing a human cannabis prescription, a long-term clinical benefit or a personal tolerance timetable.
Related: interpreting cannabis tolerance claims.
Research cited
Abraham AD; Leung EJY; Wong BA; Rivera ZMG; Kruse LC; Clark JJ; Land BB. Orally consumed cannabinoids provide long-lasting relief of allodynia in a mouse model of chronic neuropathic pain. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology (2020). doi:10.1038/s41386-019-0585-3. Findings discussed from the study abstract.
