Abstract
In the mouse vas deferens, naltrindole gave pKB values of 9.7, 8.3, and 7.5 at the delta-, mu-, and kappa-sites and in binding assays, pIC50 values of 9.6, 7.8 and 7.2 at the same sites. The affinity of naltrindole for the delta binding site was increased in the presence of sodium ions and 5'-guanylylimidophosphate. Naltrindole is, thus, a potent opioid antagonist with marked selectivity for the delta-opioid receptor.
MeSH terms
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Animals
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Electric Stimulation
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Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
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Enkephalin, D-Penicillamine (2,5)-
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Enkephalins / pharmacology
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Guanylyl Imidodiphosphate / pharmacology
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Guinea Pigs
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In Vitro Techniques
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Indoles / pharmacology*
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Male
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Mice
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Mice, Inbred Strains
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Morphinans / pharmacology*
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Muscle, Smooth / drug effects
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Muscle, Smooth / metabolism*
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Naltrexone* / analogs & derivatives*
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Narcotic Antagonists / pharmacology*
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Receptors, Opioid / metabolism*
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Receptors, Opioid, delta
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Receptors, Opioid, kappa
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Receptors, Opioid, mu
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Sodium / pharmacology
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Vas Deferens / drug effects
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Vas Deferens / metabolism
Substances
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Enkephalins
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Indoles
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Morphinans
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Narcotic Antagonists
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Receptors, Opioid
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Receptors, Opioid, delta
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Receptors, Opioid, kappa
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Receptors, Opioid, mu
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Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
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Guanylyl Imidodiphosphate
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Naltrexone
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Enkephalin, D-Penicillamine (2,5)-
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Sodium
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naltrindole