title: Long-term suppression of pain by narcotic drugs in the absence of tolerance development.
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D002908:Chronic Disease; D004361:Drug Tolerance; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000503:physiopathology*; D010880:Piperidines / Q000494:pharmacology; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D013997:Time Factors
chemical_list: D000701:Analgesics, Opioid; D001562:Benzimidazoles; D010880:Piperidines; D009270:Naloxone; D009020:Morphine