UI - 000022

AU - Abdelhamid EE

AU - Sultana M

AU - Portoghese PS

AU - Takemori AE

TI - Selective blockage of delta opioid receptors prevents the development of morphine tolerance and

dependence in mice

AB - IN: Alexandria U, Faculty of Science, Egypt LA: English AB: Studied the effect of the selective delta

antagonist naltrindole (NTI) and its nonequilibrium analog naltrindole 5'-isothiocyanate (5'-NTII) on the

development of morphine tolerance and dependence in male mice. Degree of morphine tolerance was

monitored by determining the ED-sub-5-sub-0 of morphine sulfate in a tail-flick antinociceptive assay;

degree of physical

dependence on morphine was assessed by estimating the amount of naloxone required to induce withdrawal

jumping. Both NTI and 5'-NTII suppressed the development of opiate tolerance and dependence in acute

and chronic models. The antagonists had no influence on the activity of the mu opioid receptor agonist

DAMGO. Thus, the inhibitory effect of NTI and 5'-NTII appeared to be due to their antagonist actions

solely on delta opioid receptors. Implications for the management of chronic pain are discussed. (PsycLIT

Database Copyright 1992 American Psychological Assn, all rights reserved) KP: naltrindole vs naltrindole 5-

isothiocyanate; development of morphine tolerance & dependence; male mice; implications for chronic pain

management AN: 79-00730

SO - Journal of Pharmacology and Experimental Therapeutics 1991;258:299-30