title: Morphine tolerance and sensitization in the hamster.
abstract: The effects of morphine on hamster locomotor activity were studied. Repeated administration of morphine in doses from 5 to 40 mg/kg produced systematic changes in morphine's biphasic time effect pattern: morphine's sedative effects decreased (tolerance) while morphine's excitatory effects increased (sensitization). These results extend findings of behavioral tolerance and sensitization in the hamster to a range of higher doses than those used previously.
mesh_terms: D000818:Animals; D006224:Cricetinae; D004361:Drug Tolerance; D005260:Female; D008297:Male; D008647:Mesocricetus; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D013997:Time Factors
chemical_list: D009020:Morphine