Canna~Fangled Abstracts Attenuation of morphine antinociceptive tolerance by cannabinoid CB1 and CB2 receptor antagonists. 2015 Apr 18. Altun A1, Yildirim K, Ozdemir E, Bagcivan I, Gursoy S, Durmus N. Author information Abstract Cannabinoid CB1 and…Freedom WaresApril 18, 2015