Heterogeneity of Guinea-Pig Lung Muscarinic Receptors Revealed by [3H]4-DAMP-binding
| Autor: | Yves Landry, E.-B. Haddad, J.-P. Gies, A. Trifilieff |
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| Rok vydání: | 1993 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine Stereochemistry Guinea Pigs Tritium Binding Competitive Radioligand Assay chemistry.chemical_compound Piperidines Muscarinic acetylcholine receptor Radioligand Methoctramine medicine Animals Pharmacology (medical) General Pharmacology Toxicology and Pharmaceutics Methiodide Binding site Receptor Lung Cerebral Cortex Chemistry Myocardium DAMP binding Receptors Muscarinic Pirenzepine Kinetics Biochemistry Rabbits medicine.drug |
| Zdroj: | Pulmonary Pharmacology. 6:119-127 |
| ISSN: | 0952-0600 |
| Popis: | Summary: Muscarinic receptors present in guinea-pig lung were characterized using the M 3 selective radioligand [ 3 H]4-diphenylacetoxy-N-methyl-piperidine methiodide ([ 3 H]4-DAMP). In saturation studies, [ 3 H]4-DAMP identified two populations of binding sites with approximately 4% of the sites displaying high affinity (K d =0.21 nM and B max = 10 fmol/mg prot.) while the remaining sites were low affinity ones (K d =18.11 nM and B max =269 fmol/mg prot.). In competition studies with [ 3 H]4-DAMP (0.35 nM), methoctramine and hexahydro-siladifenidol (HHSiD) identified 50 and 70% of high affinity binding sites displaying the pharmacological profile of the M 2 and the M 3 receptors, respectively. No evidence was found for high affinity [ 3 H]pirenzepine binding sites in guinea-pig lung. However, pirenzepine/[ 3 H]4-DAMP competition experiments suggested that pirenzepine recognized an equal proportion of [ 3 H]4-DAMP binding sites with intermediate and low affinity binding constants. The intermediate affinity binding constant was inconsistent with the presence of M 1 receptors and reflected more the presence of M 4 or a mixture of M 3 and M 4 receptors. The low affinity pirenzepine binding sites may represent M 2 receptors. These results provide further evidence for the occurrence of M 2 and M 3 receptors and suggest the presence of the M 4 muscarinic receptor subtype in guinea-pig lung. |
| Databáze: | OpenAIRE |
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