Extracellular cAMP inhibits P2X3 receptors in rat sensory neurones through G protein-mediated mechanism

M. V. Mamenko, I. V. Chizhmakov, T. M. Volkova, A. Verkhratsky, O. A. Krishtal

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Aim: To identify the mechanisms of P2X3 receptor inhibition by extracellular cyclic adenosine monophosphate (cAMP) in rat dorsal root ganglion (DRG) neurones. Methods: Whole-cell currents were measured in cultured DRG neurones using the combination of voltage and concentration clamp. Results: We have found that extracellular cAMP inhibits P2X3-mediated currents in a concentration- and use-dependent manner. The P2X3 currents, activated by ATP applied every 4 min, were inhibited by 55% in the presence of 10 μm cAMP and by 81% in the presence of 30 μm cAMP. At 8 min interval between ATP applications the same concentration of cAMP did not alter the currents. Addition of 0.5 mm of guanosine 5′-O-(2-thiodiphosphate) to intracellular solution blocked the inhibitory action of cAMP. The inhibitory effects of cAMP were not mimicked by extracellular application of 30 μm adenosine. Conclusions: In this paper, we demonstrate, for the first time, that extracellular application of cAMP to rat sensory neurones inhibits P2X 3 receptors via a G protein-coupled mechanism in a use-dependent manner, thus indicating the neuronal expression of specific plasmalemmal cAMP receptor.

Original languageEnglish (US)
Pages (from-to)199-204
Number of pages6
JournalActa Physiologica
Volume199
Issue number2
DOIs
StatePublished - Jan 1 2010
Externally publishedYes

Keywords

  • ATP
  • CAMP
  • CAMP receptors
  • G proteins
  • Purinergic transmission
  • Sensory neurone

ASJC Scopus subject areas

  • Physiology

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