Pharmacological characterization of a UTP-sensitive P2Y nucleotide receptor in organ cultured coronary arteries

Brent J.F. Hill, Michael Sturek

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Our lab has previously demonstrated that organ cultured coronary smooth muscle cells express a nucleotide receptor that is dramatically more responsive to UTP than non-organ cultured cells. Thus, the purpose of this study was to pharmacologically characterize this UTP-sensitive nucleotide receptor. Porcine coronary arteries were organ cultured (serum-free media, 37°C) for 4 days, and fura-2 imaging of single cells was used to measure myoplasmic Ca2+ (Cam) in response to several nucleotide agonists. A concentration-response relationship (0.01-100 μM) was generated to the nucleotide receptor agonists, UTP, UDP, ATP, ADP, and 2-MeSATP. The potency order was UTP≫UDP=ATP=ADP=2-MeSATP, thus, this nucleotide receptor is predominantly UTP-sensitive. The Cam response to 10 μM UTP was attenuated approximately 50% by the nucleotide receptor antagonists (10 and 100 μM), suramin, reactive blue 2, and pyridoxalphosphate-6-azophenyl-2′,4′-disulphonoic acid (PPADS). Depletion of the sarcoplasmic reticulum Ca2+ store with thapsigargin completely abolished the UTP-induced Cam response. In addition, the peak UTP-induced Cam increase was almost two-fold higher in a 2-mM Ca2+ solution than a 0-mM Ca2+ solution. This suggests that the UTP-induced Cam response is comprised of both Ca2+ influx and the mobilization of intracellular Ca2+ stores. Pertussis toxin reduced the UTP-induced Cam response 50%, thus, the UTP-induced increase in Cam is mediated, in part, via Gi/o. These data suggest this UTP-sensitive receptor belongs to the P2Y nucleotide receptor family; however, it does not possess pharmacological characteristics associated with any known P2Y receptor subtype.

Original languageEnglish (US)
Pages (from-to)83-88
Number of pages6
JournalVascular Pharmacology
Volume39
Issue number1-2
DOIs
StatePublished - Jul 1 2002
Externally publishedYes

Keywords

  • Concentration-response relationship
  • Myoplasmic calcium
  • PPADS
  • Pertussis toxin
  • Reactive blue 2
  • Sarcoplasmic reticulum
  • Suramin

ASJC Scopus subject areas

  • Physiology
  • Molecular Medicine
  • Pharmacology

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