Characterization and autoradiographic localization of [3H]α,β-methylene ATP binding sites in cat urinary bladder

Min Zhao, Xuenong Bo, Constance F. Neely, Geoffrey Burnstock

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

1. The characteristics and distribution of [3H]α,β-methylene ATP ([3H]α,β-MeATP), a radioligand for P(2x)-purinoceptors, binding sites in cat urinary bladder detrusor were examined. 2. Saturation analysis revealed that, in cat bladder membrane preparations, only one population of binding sites with high affinity (K(d) = 1.8 nM) was present, in contrast to other species where both high and low affinity binding sites are present. Another feature is that the density of the binding sites in the cat bladder (B(max) = 21.2 pmol/mg protein) is considerably higher (about 2-fold) than the high affinity binding component in the rat bladder membrane preparations. 3. Displacement experiments with unlabelled purinoceptor ligands indicate that [3H]α,β MeATP mainly binds to P(2x)-purinoceptors. The order of binding displacement activity was: α,β-methylene ATP, β,γ-methylene ATP>2-methylthioATP>ATP>suramin and L-β,γ-methylene ATP>>adenosine. 4. Autoradiographic study demonstrated dense specific binding sites of [3H]α,β-MeATP on detrusor smooth muscle of cat bladder. 5. The results of this study are consistent with pharmacological studies for the existence of P(2x)-purinoceptors in cat bladder.

Original languageEnglish (US)
Pages (from-to)509-512
Number of pages4
JournalGeneral Pharmacology
Volume27
Issue number3
DOIs
StatePublished - Apr 1996
Externally publishedYes

Keywords

  • [H]α,β-methylene ATP
  • ATP
  • Cat urinary bladder
  • P(2x)-purinoceptor
  • Suramin

ASJC Scopus subject areas

  • Pharmacology

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