title: Tolerance of mice to nitrous oxide.
abstract: Mice continuously exposed to a subanesthetic dose of nitrous oxide (N2O) become tolerant to nitrous oxide, as measured by an increase in their ED50 (dose required to abolish the righting reflex in 50% of animals) for N2O. The maximum increase in ED50 is approximately 0.25 atm for mice exposed to 40, 50 or 70% N2O for 2 to 3 weeks. Mice exposed to 25% N2O for 3 weeks do not develop tolerance. Mice exhibit a withdrawal syndrome when removed from the subanesthetic environment after exposure to 40 to 70% but not 25% N2O for 3 weeks. Tolerance to 50 or 70% N2O develops within 1 week and is maximal at 2 weeks. Tolerance to nitrous oxide is lost within 6 days following removal of the animals from the subanesthetic environment. Synaptic membrane fatty acid, phospholipid, and cholesterol compositions of tolerant animals are not significantly altered.
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology; D002784:Cholesterol / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D008297:Male; D008563:Membrane Lipids / Q000502:physiology; D051379:Mice; D009609:Nitrous Oxide / Q000494:pharmacology / Q000633:toxicity*; D010743:Phospholipids / Q000502:physiology; D011187:Posture / Q000187:drug effects; D012640:Seizures; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013570:Synaptic Membranes / Q000187:drug effects / Q000502:physiology
chemical_list: D008563:Membrane Lipids; D010743:Phospholipids; D002784:Cholesterol; D000110:Acetylcholinesterase; D000254:Sodium-Potassium-Exchanging ATPase; D009609:Nitrous Oxide