Muscarinic depolarization of SH-SY5Y human neuroblastoma cells as determined using oxonol V.

Abstract

Membrane potential was measured in the suspension of SH-SY5Y cells using the anionic potentiometric probe, oxonol V. The relation of fluorescence to membrane potential was assessed by increasing the external [K+] in the presence of the K+ ionophore valinomycin. The response was linear in the range of 5 to 30 mM K+ (membrane potential change of approximately 40 mV). Muscarine increased the fluorescence indicating a depolarization. The competitive inhibitory constant (112 nM) of the muscarinic antagonist pirenzepine (5,11-dihydro-11-([4-methyl-1-piperazinyl]acetyl)-6H-pyrido[2,3-b] (1,4)benzodiazepin-6-one-dihydrochloride) suggests that Hm1 receptors are not involved. The protein kinase C inhibitor, GF 109203X (3-[1-(3-demethylaminopropyl)-indol-3-yl]-3-(indol-3-yl)-maleimide ), and a reduction of extracellular Na+ both produced an additive partial inhibition. The results suggest that muscarinic receptors depolarize these cells by separate Na(+)-dependent and -independent mechanisms, the Na(+)-independent mechanism being protein kinase C-dependent.

• Authors: J P Kukkonen, R Hautala, K E Akerman
• Journal: Neuroscience letters (Neurosci Lett) Vol. 212 Issue 1 Pg. 57-60 (Jul 05 1996) ISSN: 0304-3940 [Print] Ireland
• PMID: 8823762 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Fluorescent Dyes
• Indicators and Reagents
• Isoxazoles
• Muscarinic Agonists
• Receptors, Muscarinic
• Tetrodotoxin
• Egtazic Acid
• oxonol V
• Muscarine
• 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid

Topics

• Egtazic Acid (analogs & derivatives, pharmacology)
• Electrophysiology (methods)
• Fluorescent Dyes
• Humans
• Indicators and Reagents (pharmacology)
• Isoxazoles
• Membrane Potentials (physiology)
• Muscarine (pharmacology)
• Muscarinic Agonists (pharmacology)
• Neuroblastoma
• Receptors, Muscarinic (physiology)
• Tetrodotoxin (pharmacology)
• Time Factors
• Tumor Cells, Cultured (chemistry, physiology)