Selective opioid receptor agonist and antagonist displacement of [3H]naloxone binding in amphibian brain
| Autor: | David R. Wallace, Leslie C. Newman, Craig W. Stevens |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Agonist
medicine.drug_class Narcotic Antagonists Receptors Opioid mu (+)-Naloxone Biology Pharmacology Tritium Binding Competitive Naltrexone Radioligand Assay Opioid receptor Receptors Opioid delta medicine Animals Receptor Dose-Response Relationship Drug Naloxone Receptors Opioid kappa Rana pipiens Antagonist Brain Molecular biology Kinetics Opioid Receptors Opioid medicine.drug |
| Zdroj: | European journal of pharmacology. 397(2-3) |
| ISSN: | 0014-2999 |
| Popis: | Opioid receptor ligands have been shown to elicit antinociception in mammals through three distinct types of receptors designated as mu, delta and kappa. These opioid receptors have been characterized and cloned in several mammalian species. Radioligand binding techniques were employed to characterize the sites of opioid action in the amphibian, Rana pipiens. Naloxone is a general opioid receptor antagonist which has not been characterized in R. pipiens. Kinetic analyses of [3H]naloxone in the amphibian yielded a K(D) of 6.84 nM while the experimentally derived K(D) value from saturation experiments was found to be 7.11 nM. Density data were also determined from saturation analyses which yielded a B(max) of 2170 fmol/mg. Additionally, K(i) values were calculated in competition studies for various unlabelled mu-, delta- and kappa-opioid receptor ligands to isolate their site of action. Highly selective antagonists for mu-, delta- and kappa-opioid receptors yielded nearly identical K(i) values against [3H]naloxone. |
| Databáze: | OpenAIRE |
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