title: Development of narcotic addiction, tolerance and cross-tolerance.
mesh_terms: D000818:Animals; D004361:Drug Tolerance; D004723:Endorphins / Q000502:physiology; D004745:Enkephalins / Q000502:physiology; D006801:Humans; D009294:Narcotics / Q000494:pharmacology; D009712:Nucleotides, Cyclic / Q000502:physiology; D009293:Opioid-Related Disorders / Q000378:metabolism*; D051381:Rats
chemical_list: D004723:Endorphins; D004745:Enkephalins; D009294:Narcotics; D009712:Nucleotides, Cyclic