Binding of naloxone to human T lymphocytes.
Purified T lymphocytes have a specific binding site for naloxone, the opiate antagonist. The KD for the site was 50.6 +/- 2.4 nM, while the Hill coefficient (n) was 1.67 +/- 0.16, indicating a degree of positive cooperativity of ligand binding. The bound naloxone was partially displaceable by various opiate agonists including morphine (56%), beta-endorphin (61%), met5- and leu5-enkephalin (40% each), [D-ala2, D-leu5]-enkephalin (78%) and [D-ala2, D-leu5]-enkephalinamide (66%). Virtually all of the binding capacity was recovered in the particulate membrane fraction after sonic lysis of the cells. There was great interindividual variability in Bmax between samples, suggesting a possible mechanistic basis for the variability in drug action seen between different individuals.
Madden
J J
JJ
Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30322.
Donahoe
R M
RM
Zwemer-Collins
J
J
Shafer
D A
DA
Falek
A
A
D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism; D003470:Culture Media; D004743:Enkephalin, Leucine / Q000378:metabolism; D004744:Enkephalin, Methionine / Q000378:metabolism; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D009020:Morphine / Q000378:metabolism; D009270:Naloxone / Q000378:metabolism*; D011957:Receptors, Opioid / Q000378:metabolism*; D013010:Sonication; D013601:T-Lymphocytes / Q000378:metabolism*; D001615:beta-Endorphin / Q000378:metabolism
D003470:Culture Media; D011957:Receptors, Opioid; C034565:naloxone receptor; D009270:Naloxone; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; D009020:Morphine; D005978:Glutathione