Characterization of the interaction of the cervane alkaloid, imperialine, at muscarinic receptors in vitro
| Autor: | Eric Stefanich, G.C. Harris, A O Sullivan, Roger L. Whiting, Richard M. Eglen, H Cox |
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| Rok vydání: | 1992 |
| Předmět: |
Male
medicine.medical_specialty Guinea Pigs Muscarinic Antagonists Biology Rats Sprague-Dawley chemistry.chemical_compound Radioligand Assay Alkaloids Dogs Ileum Internal medicine Muscarinic acetylcholine receptor medicine Animals Gastric Fundus Receptor Pharmacology Plants Medicinal Antagonist Muscarinic acetylcholine receptor M3 Seminal Vesicles Muscarinic acetylcholine receptor M2 Dioxolanes Muscle Smooth General Medicine Muscarinic acetylcholine receptor M1 Molecular biology Receptors Muscarinic Rats Kinetics Endocrinology chemistry Himbacine Female Rabbits Cevanes Muscle Contraction |
| Zdroj: | Naunyn-Schmiedeberg's archives of pharmacology. 346(2) |
| ISSN: | 0028-1298 |
| Popis: | The action of the cervane alkaloid, imperialine, has been assessed at M1, M2 and M3 receptors in functional assays and at M1, M2, M3 and putative M4 sites in binding studies. In functional studies, imperialine acted as a selective surmountable antagonist at M2 receptors in guinea-pig isolated atria and uterus (-log KB = 7.7 and 7.4, respectively), in comparison to M1 receptors in canine isolated saphenous vein (-log KB = 6.9) or M3 receptors in a range of guinea-pig isolated smooth muscles including ileum, trachea, fundus, seminal vesicle or oesophagus (-log KB = 6.6-6.8). In rat aorta, the -log KB value at the M3 receptor (5.9) was slightly, but significantly, lower. In competition radioligand binding studies, imperialine was also selective toward to M2 sites in rat myocardium (-log Ki = 7.2) with respect to M1 and M3 sites (rat cerebral cortex, rat submaxillary gland; -log Ki = 6.1 and 5.7, respectively). However, it did not significantly discriminate between rat cardiac M2 sites and putative M4 sites in rabbit lung (-log Ki = 6.9). Imperialine resembles the alkaloid himbacine in terms of its pharmacological profile at muscarinic receptor subtypes in that it acts as an M2 selective antagonist with respect to M1 or M3 sites. It may also provide a second, commercially available, antagonist with which to discriminate between M1 and M4 receptors. |
| Databáze: | OpenAIRE |
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