α-Conotoxin ImI Inhibits the α-Bungarotoxin-Resistant Nicotinic Response in Bovine Adrenal Chromaffin Cells
| Autor: | John Gehrmann, N. M. Broxton, B. G. Livett, D. G. Satchell, J. G. Down, Paul F. Alewood |
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| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty alpha7 Nicotinic Acetylcholine Receptor Chromaffin Cells Molecular Sequence Data Drug Resistance Mollusk Venoms Receptors Nicotinic Niacin Biochemistry Neuromuscular junction Potassium Chloride Cellular and Molecular Neuroscience Catecholamines Internal medicine medicine Animals Amino Acid Sequence Conus imperialis Rats Inbred BUF Muscle Skeletal Acetylcholine receptor Motor Neurons Dose-Response Relationship Drug biology Calcium Radioisotopes Bungarotoxin Bungarotoxins biology.organism_classification Molecular biology Acetylcholine Rats Nicotinic acetylcholine receptor medicine.anatomical_structure Nicotinic agonist Endocrinology Chromaffin cell Cattle Conotoxins Adrenal medulla Oligopeptides |
| Zdroj: | Journal of Neurochemistry. 72:1656-1662 |
| ISSN: | 0022-3042 |
| DOI: | 10.1046/j.1471-4159.1999.721656.x |
| Popis: | The activity of alpha-conotoxin (alpha-CTX) lml, from the vermivorous marine snail Conus imperialis, has been studied on mammalian nicotinic receptors on bovine chromaffin cells and at the rat neuromuscular junction. Synthetic alpha-CTX lml was a potent inhibitor of the neuronal[ nicotinic response in bovine adrenal chromaffin cells (IC50 = 2.5 mu M, log IC50 = 0.4 +/- 0.07), showing competitive inhibition of nicotine-evoked catecholamine secretion. (alpha-CTX lml also inhibited nicotine-evoked Ca-45(2+) uptake but not Ca-45(2+) uptake stimulated by 56 mM Kr. In contrast, alpha-CTX lml had no effect at the neuromuscular junction over the concentration range 1-20 mu M. Bovine chromaffin cells are known to contain the alpha 3 beta 4, alpha 7, and (possibly) alpha 3 beta 4 alpha 5 subtypes. However, the secretory response of bovine chromaffin cells is not inhibited by alpha-bungarotoxin, indicating that alpha 7 nicotinic receptors are not involved. We propose that alpha-CTX lml interacts selectively with the functional (alpha 3 beta 4 or alpha 3 beta 4 alpha 5) nicotinic acetylcholine receptor to inhibit the neuronal-type nicotinic response in bovine chromaffin cells. |
| Databáze: | OpenAIRE |
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