4Gan TJ, Ginsberg B, Glass PSA, et al. Opioid-sparing effects of a low-dose infusion of naloxone in patient-administered morphine sulfate. Anesthesiology, 1997, 87:1075～1081.
5Crain SM, Shen KF. Antagonists of excitatory opioid recepto r functions enhance morphine's analgesic potency and attenuate opioid tolerance/dependence liability.Pain, 2000, 84:121～131.
6Kurashi Y, Sugimoto M, Hamada T, et al. Noxious stimuli and met-enkephalin release from nucleus reticularis gigantocelluralis. Brain Research Bulletin, 1984, 72: 123～127.
7Paronis CA, Holtzman SG. Increased analgesic potency of mu agonists after continuous naloxone infusion in rats. J Pharmacol Exp Ther, 1991,259:582～589.
