Abstract
The agonist radioligand (-)-N6-[125I]-p-hydroxyphenylisopropyladenosine ([125I]HPIA) was used to characterize adenosine recognition sites in porcine atrial membranes. [125I]HPIA showed saturable binding to an apparently homogeneous population of sites with a maximum binding capacity of 35 ± 3 fmol/mg of protein and an equilibrium dissociation constant of 2.5 ± 0.4 nM. Kinetic experiments were performed to address the molecular mechanism of [125I]HPIA binding in porcine atrial membranes. [125I]HPIA apparently interacts with the cardiac adenosine receptor in a simple bimolecular reaction. A kinetically derived [125I]HPIA dissociation constant (2.4 nM) was in good agreement with that parameter measured at equilibrium. Guanyl nucleotides negatively modulated [125I]HPIA binding by increasing its rate of dissociation. This finding is consonant with the formation of a ternary complex in porcine atrial membranes, consisting of ligand, receptor, and guanyl nucleotide-binding protein. Prototypic adenosine receptor agonists and antagonists inhibited specific binding in a manner consistent with the labeling of an A1 adenosine receptor. The results of these experiments suggest that the adenosine receptor present in porcine atrial membranes, as labeled by [125I]HPIA, is of the A1 subtype.
| Original language | English |
|---|---|
| Pages (from-to) | 334-339 |
| Number of pages | 6 |
| Journal | Molecular Pharmacology |
| Volume | 34 |
| Issue number | 3 |
| State | Published - 1988 |
| Externally published | Yes |
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- Pharmacology
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Characterization of agonist radioligand interactions with porcine atrial A1 adenosine receptors. / Leid, M.; Schimerlik, M. I.; Murray, Thomas F.
In: Molecular Pharmacology, Vol. 34, No. 3, 1988, p. 334-339.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization of agonist radioligand interactions with porcine atrial A1 adenosine receptors
AU - Leid, M.
AU - Schimerlik, M. I.
AU - Murray, Thomas F.
PY - 1988
Y1 - 1988
N2 - The agonist radioligand (-)-N6-[125I]-p-hydroxyphenylisopropyladenosine ([125I]HPIA) was used to characterize adenosine recognition sites in porcine atrial membranes. [125I]HPIA showed saturable binding to an apparently homogeneous population of sites with a maximum binding capacity of 35 ± 3 fmol/mg of protein and an equilibrium dissociation constant of 2.5 ± 0.4 nM. Kinetic experiments were performed to address the molecular mechanism of [125I]HPIA binding in porcine atrial membranes. [125I]HPIA apparently interacts with the cardiac adenosine receptor in a simple bimolecular reaction. A kinetically derived [125I]HPIA dissociation constant (2.4 nM) was in good agreement with that parameter measured at equilibrium. Guanyl nucleotides negatively modulated [125I]HPIA binding by increasing its rate of dissociation. This finding is consonant with the formation of a ternary complex in porcine atrial membranes, consisting of ligand, receptor, and guanyl nucleotide-binding protein. Prototypic adenosine receptor agonists and antagonists inhibited specific binding in a manner consistent with the labeling of an A1 adenosine receptor. The results of these experiments suggest that the adenosine receptor present in porcine atrial membranes, as labeled by [125I]HPIA, is of the A1 subtype.
AB - The agonist radioligand (-)-N6-[125I]-p-hydroxyphenylisopropyladenosine ([125I]HPIA) was used to characterize adenosine recognition sites in porcine atrial membranes. [125I]HPIA showed saturable binding to an apparently homogeneous population of sites with a maximum binding capacity of 35 ± 3 fmol/mg of protein and an equilibrium dissociation constant of 2.5 ± 0.4 nM. Kinetic experiments were performed to address the molecular mechanism of [125I]HPIA binding in porcine atrial membranes. [125I]HPIA apparently interacts with the cardiac adenosine receptor in a simple bimolecular reaction. A kinetically derived [125I]HPIA dissociation constant (2.4 nM) was in good agreement with that parameter measured at equilibrium. Guanyl nucleotides negatively modulated [125I]HPIA binding by increasing its rate of dissociation. This finding is consonant with the formation of a ternary complex in porcine atrial membranes, consisting of ligand, receptor, and guanyl nucleotide-binding protein. Prototypic adenosine receptor agonists and antagonists inhibited specific binding in a manner consistent with the labeling of an A1 adenosine receptor. The results of these experiments suggest that the adenosine receptor present in porcine atrial membranes, as labeled by [125I]HPIA, is of the A1 subtype.
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M3 - Article
C2 - 3047553
AN - SCOPUS:0023772566
VL - 34
SP - 334
EP - 339
JO - Molecular Pharmacology
JF - Molecular Pharmacology
SN - 0026-895X
IS - 3
ER -