title: Periaqueductal gray naloxone microinjections in morphine-dependent rats: hyperalgesia without "classical" withdrawal.
mesh_terms: D000818:Animals; D002535:Cerebral Aqueduct; D006801:Humans; D007267:Injections; D007274:Injections, Intraperitoneal; D009021:Morphine Dependence / Q000503:physiopathology*; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D013375:Substance Withdrawal Syndrome / Q000139:chemically induced / Q000503:physiopathology*
chemical_list: D009270:Naloxone