title: Morphine dependence and in vivo turnover of acetylcholine in whole mouse brain.
abstract: Turnover rates of acetylcholine (ACh) were estimated in mouse brain after intravenous injection of phosphoryl(Me-14C)choline by applying principles of steady-state kinetics to the change with time of choline and ACh specific radioactivities. Turnover rate of brain ACh was estimated: 1) 45 minutes after a single injection of morphine (350 mumol/kg); 2) 3.5 days after implantation of a morphine pellet (250 mumol/pellet); 3) 15 minutes after 24 mumol/kg of naloxone to precipitate withdrawal in mice implanted with morphine pellets for 3.5 days; and 4) 15 minutes after 24 mumol/kg of naloxone. Brain ACh turnover rate was unchanged in mice that were given a single injection of morphine but was increased significantly in mice that had been made physically dependent upon morphine. During naloxone-precipitated withdrawal, the brain ACh turnover rate was found to be equal to that of mice treated only with naloxone.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D004343:Drug Implants; D006801:Humans; D007274:Injections, Intraperitoneal; D007700:Kinetics; D008297:Male; D051379:Mice; D008954:Models, Biological; D009020:Morphine / Q000008:administration & dosage; D009021:Morphine Dependence / Q000378:metabolism* / Q000503:physiopathology; D009270:Naloxone / Q000494:pharmacology; D013375:Substance Withdrawal Syndrome / Q000378:metabolism / Q000503:physiopathology; D013997:Time Factors
chemical_list: D004343:Drug Implants; D009270:Naloxone; D009020:Morphine; D002794:Choline; D000109:Acetylcholine