5-HT2A receptor-mediated outward current in C6 glioma cells is mimicked by intracellular IP3 release

• Published in: Neuroreport Vol. 5; no. 10; p. 1245
• Main Authors: Bartrup, J T, Newberry, N R
• Format: Journal Article
• Language: English
• Published: England 02.06.1994
• Subjects: Animals; Brain Neoplasms - metabolism; Calcium - physiology; Electrophysiology; Glioma - metabolism; Inositol 1,4,5-Trisphosphate - metabolism; Ion Channels - drug effects; Ion Channels - metabolism; Membrane Potentials - drug effects; Membrane Potentials - physiology; Potassium Channels - drug effects; Potassium Channels - metabolism; Rats; Receptors, Serotonin - metabolism; Receptors, Serotonin - physiology; Serotonin - pharmacology; Tumor Cells, Cultured
• ISSN: 0959-4965; 1473-558X
• DOI: 10.1097/00001756-199406020-00022

The C6 glioma cell line possesses 5-HT2A receptors that have been shown to increase intracellular calcium levels. We have studied the electrophysiological response of these cells to 5-HT using the whole-cell recording method. Under voltage-clamp, 5-hydroxytryptamine (5-HT) produced an outward current in these cells which was inhibited by extracellularly applied ketanserin and spiperone and by EGTA (10 mM) in the recording electrode. The 5-HT induced response could be mimicked by intracellular photolytic release of inositol (1,4,5) trisphosphate (IP3) from caged molecules. The reversal potentials for the IP3- and 5-HT-induced responses were closely matched. The data indicates that the outward current is likely to be mediated by 5-HT2A receptors stimulating IP3 production which increases intracellular calcium leading to the opening of calcium-activated potassium channels.