Introduction of the 5-HT3B subunit alters the functional properties of 5-HT3 receptors native to neuroblastoma cells

A. Stewart, P. A. Davies, E. F. Kirkness, P. Safa, T. G. Hales (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

The identification of a second 5-HT(3) (5-HT(3B)) subunit provides an explanation for 5-HT(3) receptor heterogeneity. We investigated whether introduction of recombinant 5-HT(3B) subunits would alter the functional properties of mouse neuroblastoma 5-HT(3) receptors. RT-PCR analysis revealed that NB41A3 cells contain mRNAs encoding 5-HT(3A) and 5-HT(3B) subunits. 5-HT increased intracellular Ca(2+) concentration ([Ca(2+)](i)) and caused the concentration-dependent activation of inward currents recorded at -60 mV. Both actions of 5-HT were antagonized by ondansetron. The 5-HT concentration-response relationship of NB41A3 cells was indistinguishable from that of the related NG108-15 cell line. The selective 5-HT(3)-receptor agonist mCPBG also elevated [Ca(2+)](i) and activated inward currents. 2-M-5HT was less efficacious than 5-HT as an activator of 5-HT(3) receptors in NB41A3 cells and did not significantly increase [Ca(2+)](i). The 5-HT induced increase in [Ca(2+)](i) did not involve caffeine- or thapsigargin-sensitive intracellular Ca(2+) stores. The introduction of the 5-HT(3B) subunit by transient transfection of NB41A3 cells caused 5-HT to become less potent as an activator of 5-HT(3) receptors and altered the kinetics of 5-HT activated currents so that they resembled currents mediated by 5-HT(3AB) receptors. The 5-HT(3B) subunit also abolished the 5-HT induced [Ca(2+)](i) increase seen in untransfected NB41A3 cells. These data are consistent with the hypothesis that NB41A3 cells predominantly express homomeric 5-HT(3A) receptors that become heteromeric 5-HT(3AB) receptors upon introduction of the recombinant 5-HT(3B) subunit.

Original languageEnglish
Pages (from-to)214-23
Number of pages10
JournalNeuropharmacology
Volume44
Issue number2
Early online date22 Jan 2003
DOIs
Publication statusPublished - Feb 2003

Keywords

  • Animals
  • Biguanides/pharmacology
  • Calcium/metabolism
  • Cell Differentiation/drug effects
  • Cell Line/classification
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Fluorescence
  • Gene Expression
  • Green Fluorescent Proteins
  • Luminescent Proteins/metabolism
  • Mice
  • Molecular Sequence Data
  • Neuroblastoma/classification
  • Ondansetron/pharmacology
  • Patch-Clamp Techniques
  • Protein Subunits/metabolism
  • RNA, Messenger/analysis
  • Rats
  • Receptors, Serotonin/chemistry
  • Receptors, Serotonin, 5-HT3
  • Recombinant Fusion Proteins/physiology
  • Recombinant Proteins/chemistry
  • Reverse Transcriptase Polymerase Chain Reaction
  • Serotonin/analogs & derivatives
  • Serotonin Antagonists/pharmacology
  • Serotonin Receptor Agonists/pharmacology
  • Transfection

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