Abstract
Ca2+ mobilizations in SH-SY5Y and IMR-32 human neuroblastoma cell lines were measured using the fluorescent Ca2+ indicator fura-2. A variety of antagonists (atropine, pirenzepine, 4-DAMP and N-methyl-scopolamine) inhibited carbamyl choline-induced transient Ca2+ mobilization both in a competitive and a noncompetitive manner. The apparent noncompetitive inhibition constants were lower in IMR-32 than in SH-SY5Y cells even when the competitive inhibition constants were similar. This may relate to the previously reported differential expression of muscarinic receptor subtypes in these cell lines.
MeSH terms
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Atropine / pharmacology*
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Calcium / metabolism*
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Fura-2
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Humans
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Kinetics
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Muscarinic Antagonists
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N-Methylscopolamine
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Neuroblastoma
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Parasympatholytics / pharmacology*
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Piperidines / pharmacology*
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Pirenzepine / pharmacology*
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Receptors, Muscarinic / drug effects
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Receptors, Muscarinic / physiology*
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Scopolamine Derivatives / metabolism
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Scopolamine Derivatives / pharmacology*
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Spectrometry, Fluorescence
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Tumor Cells, Cultured
Substances
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Muscarinic Antagonists
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Parasympatholytics
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Piperidines
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Receptors, Muscarinic
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Scopolamine Derivatives
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Pirenzepine
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Atropine
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4-diphenylacetoxy-1,1-dimethylpiperidinium
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Calcium
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Fura-2
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N-Methylscopolamine