JNK Inhibition Delayed THC Tolerance but Accelerated Another Cannabinoid’s Tolerance in Mice
A signaling-pathway intervention did not affect all cannabinoid agonists in the same direction. In mouse experiments, JNK inhibition reduced tolerance to selected THC effects while accelerating tolerance to CP55,940.
Several pain models were included
Researchers used acute thermal, inflammatory and cisplatin-related neuropathic pain models. The experiments compared THC with other cannabinoid agonists and included wild-type and desensitization-resistant receptor-mutant mice. The inhibitor SP600125 was an experimental probe rather than a tested clinical cannabis treatment.
The challenge compound changed the result
Pretreatment attenuated tolerance to THC-related antinociceptive or anti-allodynic effects in selected conditions. It did not produce the same benefit for WIN55,212-2, and it accelerated tolerance to CP55,940 in the tested models. The pathway therefore could not be summarized as a universal cannabinoid-tolerance switch.
Other drug effects complicate mechanism claims
The inhibitor itself showed some anti-allodynic activity in one experimental setting. A change during combined treatment must be interpreted alongside those independent effects. Genotype, dose and the particular nociceptive assay also affected the comparisons.
The practical research lesson
A mechanism identified with THC should be retested before being extended to a synthetic agonist or another pain condition. These animal findings do not establish that inhibiting JNK safely prolongs cannabis benefit in patients. They support evaluating the actual drug–pathway–endpoint combination, including results that run in the opposite direction from the hoped-for treatment effect.
Related analysis: evaluating cannabis tolerance claims.
Primary research
Henderson-Redmond AN; Nealon CM; Davis BJ; Yuill MB; Sepulveda DE; Blanton HL; Piscura MK; Zee ML; Haskins CP; Marcus DJ; Mackie K; Guindon J; Morgan DJ. c-Jun N terminal kinase signaling pathways mediate cannabinoid tolerance in an agonist-specific manner. Neuropharmacology (2020). DOI: 10.1016/j.neuropharm.2019.107847.
