title: Morphine tolerance in genetically selected rats induced by chronically elevated saccharin intake.
abstract: Rats of line LC2-Hi that drank about 50 milliliters of a highly palatable saccharin solution daily for 28 consecutive days did not show morphine analgesia or an opioid form of stress-induced analgesia and were not responsive to naloxone. These findings support the idea that chronically elevated saccharin intake may cause increased release and utilization of endogenous opiates.
mesh_terms: D000818:Animals; D004361:Drug Tolerance; D004723:Endorphins / Q000502:physiology; D009020:Morphine / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology; D051381:Rats; D012439:Saccharin / Q000494:pharmacology*; D013312:Stress, Physiological / Q000503:physiopathology*
chemical_list: D004723:Endorphins; D009020:Morphine; D012439:Saccharin