title: Morphine analgesia and tolerance: a possible role of cyclic AMP.
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000698:Analgesia; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D004361:Drug Tolerance; D009020:Morphine / Q000494:pharmacology*; D009638:Norepinephrine / Q000502:physiology; D051381:Rats; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission
chemical_list: D009020:Morphine; D000242:Cyclic AMP; D000241:Adenosine; D009638:Norepinephrine