Cholinergic responses in cloned human TE671/RD tumour cells

Francesca Grassi, Aldo Giovannelli, Sergio Fucile, Elisabetta Mattei, Fabrizio Eusebi

Research output: Contribution to journalArticlepeer-review

Abstract

The cholinergic responses of the human tumour cell line TE671/RD were examined using digital Ca2+ imaging fluorescence microscopy and patch-clamp measurements. In response to stimulation of the muscarinic acetylcholine (ACh) receptor (mAChR), the intracellular concentration of Ca2+ ([Ca2+]i) rose about two-fold, in parallel with inositol 1,4,5-trisphosphate accumulation, measured by chromatographic techniques. By contrast, there was no increment of [Ca2+]i upon stimulation of the nicotinic ACh receptor (nAChR), nor after caffeine application. Electrophysiological experiments showed that TE671/RD cells lack functional voltage-activated Ca2+ channels. The stimulation of the nAChR induced transient whole-cell currents (IACh). Little or no current was detected in isotonic extracellular Ca2+, with Cs+ in the patch pipette. Cell pretreatment with muscarine reduced IACh by about 20%, without consistent modifications of current kinetics. Muscarine applied to the extra-patch membrane under the cell-attached configuration had no obvious effect on ACh-evoked unitary events. In conclusion, in human TE671/ RD cells, muscarinic stimulation increases [Ca2+]i, while nicotinic stimulation does not. In addition, the nAChR exhibits peculiar ion permeability properties and is not functionally regulated by the breakdown of phosphoinositides.

Original languageEnglish
Pages (from-to)117-125
Number of pages9
JournalPflugers Archiv European Journal of Physiology
Volume425
Issue number1-2
DOIs
Publication statusPublished - Oct 1993

Keywords

  • Ca imaging
  • Inositol 1,4,5-trisphosphate
  • Muscarinic acetylcholine receptor
  • Nicotinic acetylcholine receptor
  • Phosphoinositide turn-over
  • TE671/RD cell line

ASJC Scopus subject areas

  • Physiology

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