Apparent noncompetitive antagonism of muscarinic receptor mediated Ca2+ mobilization by some muscarinic antagonists.

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.

• Authors: J Kukkonen, K E Akerman
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 189 Issue 2 Pg. 919-24 (Dec 15 1992) ISSN: 0006-291X [Print] United States
• PMID: 1472064 (Publication Type: Journal Article)

Chemical References

• Muscarinic Antagonists
• Parasympatholytics
• Piperidines
• Receptors, Muscarinic
• Scopolamine Derivatives
• Pirenzepine
• Atropine
• 4-diphenylacetoxy-1,1-dimethylpiperidinium
• Calcium
• Fura-2
• N-Methylscopolamine

Topics

• Atropine (pharmacology)
• Calcium (metabolism)
• Fura-2
• Humans
• Kinetics
• Muscarinic Antagonists
• N-Methylscopolamine
• Neuroblastoma
• Parasympatholytics (pharmacology)
• Piperidines (pharmacology)
• Pirenzepine (pharmacology)
• Receptors, Muscarinic (drug effects, physiology)
• Scopolamine Derivatives (metabolism, pharmacology)
• Spectrometry, Fluorescence
• Tumor Cells, Cultured