High-Dose Anandamide Regimens Produced Cross-Tolerance While One Gut-Related Measure Stayed Sensitive
In a mouse study, repeated high-dose anandamide-related treatment produced tolerance and THC cross-tolerance on several tests, but not on reduced defecation. Lower-dose regimens did not produce the same broad tolerance pattern.
Two endogenous ligands and several doses were tested
Female mice from two strains received daily injections of anandamide or a related endogenous ligand for two weeks. Testing after the final exposure examined movement, ring catalepsy, temperature and hot-plate antinociception. These controlled injected regimens differ from ordinary endogenous cannabinoid release.
Dose history changed the finding
High-dose exposure produced tolerance to anandamide and cross-tolerance to THC across the reported behavioral tests. Lower tested doses did not. One week after anandamide treatment ended, tolerance was no longer present in the reported comparison. This is an experimental recovery observation, not a human tolerance-break prescription.
Reduced defecation was an exception
Tolerance was not observed for reduced defecation in the open field, used as a measure related to intestinal hypomotility. The authors suggested receptor-related differences as a possible explanation, but the abstract does not establish a specific mechanism for this endpoint exception.
The study supports both dose dependence and endpoint selectivity. A claim that anandamide tolerance always develops would omit the low-dose results, while a claim that it eliminates every response would omit the gut-related finding. Neither endogenous origin nor shared cannabinoid activity makes the compounds interchangeable with THC.
Related: interpreting cannabis tolerance claims.
Research cited
Fride E. Anandamides: tolerance and cross-tolerance to delta 9-tetrahydrocannabinol. Brain research (1995). doi:10.1016/0006-8993(95)00790-w. Findings discussed from the study abstract.
