Estimates of antagonist affinities at P2X purinoceptors in rat vas deferens.

@article{Khakh1994EstimatesOA,
  title={Estimates of antagonist affinities at P2X purinoceptors in rat vas deferens.},
  author={Baljit S. Khakh and Anton D. Michel and Patrick P. A. Humphrey},
  journal={European journal of pharmacology},
  year={1994},
  volume={263 3},
  pages={
          301-9
        }
}
P2-purinoceptor antagonists: I. Blockade of P2-purinoceptor subtypes and ecto-nucleotidases by small aromatic isothiocyanato-sulphonates
TLDR
The results indicate that the isothiocyanato residue as well as the aromatic core are essential for P2-purinoceptor blockade and no simple structure-activity relationship for the P2Y- purinoceptor and the ATP-degrading ecto-nucleotidases can be derived beyond the apparent lack of a major influence of the position of the substituents.
Reactive red 2: a P2y-selective purinoceptor antagonist and an inhibitor of ecto-nucleotidase
TLDR
The results indicate that reactive red 2 is a relatively potent antagonist at both PZx-purinoceptors in rat vas deferens and P2Y-purinceptor subtypes in guinea-pig taenia coli, with a 15 fold selectivity for the P2y-Purinoceptor.
P2-purinoceptor antagonists: II. Blockade of P2-purinoceptor subtypes and ecto-nucleotidases by compounds related to Evans blue and trypan blue
TLDR
Among active compounds, apparent purinoceptor affinity and ecto-nucleotidase blockade increase with the size of the molecules up to Evans blue and trypan blue themselves; introduction of a central ethylene bridge does not result in a further gain in potency.
P2-receptor antagonists: IV. Blockade of P2-receptor subtypes and ecto-nucleotidases by compounds related to reactive blue 2
TLDR
Effects of reactive blue 2 and twelve structurally related compounds were studied on contractions of the rat vas deferens elicited by α,β-methylene ATP, relaxations of the carbachol-precontracted guinea-pig taenia coli eliciting by adenosine 5′-O-(2-thiodiphosphate) (ADPβS), and the degradation of ATP by rat vasdeferens tissue.
Structure-activity relationships of pyridoxal phosphate derivatives as potent and selective antagonists of P2X1 receptors.
TLDR
None of the analogues were more potent at P2X7 and P2Y1 receptors than 2, which acted in the micromolar range at these two subtypes, and 5-Methylphosphonate substitution, anticipated to increase stability to hydrolysis, preserved P2 receptor potency.
Concomitant blockade of P2X-receptors and ecto-nucleotidases by P2-receptor antagonists: functional consequences in rat vas deferens
TLDR
The results confirm the frequent combination, in one antagonist molecule, of P2-receptor blockade and blockade of ecto-nucleotidases and underlies the effect of such compounds on contractions of the vas deferens elicited by ATP.
P2-purinoceptor antagonists: III. Blockade of P2-purinoceptor subtypes and ecto-nucleotidases by compounds related to suramin
TLDR
NF023 is interesting because it is P2X- versus P2Y-selective and, in addition, the compound with the highest P2x- versus ecto-nucleotidase-selectivity presently available and BSt101 resembled NF023 in potency at all three sites, indicating that the possession of a second naphthalene-trisulphonate group is not a prerequisite for relatively high affinity.
Evaluation of P2-purinoceptor antagonists at two relaxation-mediating P2-purinoceptors in guinea-pig taenia coli
TLDR
The selective effect of XAMR0721 against α,β-MeATP confirms the existence of two relaxation-mediating P2-purinoceptors in guinea-pig taenia coli and shows that reactive blue 2, suramin, iso-PPADS, pyridoxal 5-phosphate and trypan blue have little selectivity for any of the three receptors.
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References

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PPADS selectively antagonizes P2X‐purinoceptor‐mediated responses in the rabbit urinary bladder
TLDR
Binding studies demonstrated that the antagonistic effect of PPADS is via a direct interaction with P2X‐purinoceptor‐mediated responses in rabbit vas deferens, and its ability to antagonize contractions evoked by α,β‐methylene ATP, carbachol and electrical field stimulation in the rabbit urinary bladder detrusor muscle.
Suramin is a slowly‐equilibrating but competitive antagonist at P2x‐receptors in the rabbit isolated ear artery
TLDR
This analysis provides the first evidence that suramin is a genuine competitive P2x‐receptor antagonist and fulfilled all criteria for simple competition.
P1- and P2-purinoceptor subtypes--an update.
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  • 1990
TLDR
Biochemical, ligand binding and pharmacological studies clearly indicate that the P1-purinoceptor can be subdivided into the A1- and A2-subtypes and that each can be separated into at least two subtypes.
Purinoceptor nomenclature: A status report
TLDR
It was recommended from this meeting that adenosine receptors, in addition to the classical A1, A2a, and A2b receptors, be further described by numerical subscript, i.e., A3, A4, until such time as pharmacological and molecular biological data provided evidence for their relationship, if any, to the A1/A2, classes.
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