Source 1review2000British Journal of Pharmacology
Toolkit/[3H]-NECA
[3H]-NECA
Also known as: NECA
Taxonomy: Technique Branch / Method. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
The non-selective agonist NECA (A1, A2A, A2B, A3) was the first pharmacological tool to be used for labelling the A2A receptor in the rat brain but it was also found to bind to different affinity states and subtypes of adenosine receptors... the majority of the [3H]-NECA binding to human platelet membranes is to non-receptor sites.
Usefulness & Problems
Why this is useful
This ligand was used as an early radiolabeling tool for adenosine receptor studies. In the review, it is mainly discussed as a problematic probe for human platelet A2A receptor characterization.; early radioligand labeling attempts for adenosine receptor studies
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This ligand was used as an early radiolabeling tool for adenosine receptor studies. In the review, it is mainly discussed as a problematic probe for human platelet A2A receptor characterization.
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early radioligand labeling attempts for adenosine receptor studies
Problem solved
It provided an initial way to label adenosine receptor-related binding sites before more selective A2A tools were available.; provided an initial pharmacological tool for receptor labeling before more selective ligands were available
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It provided an initial way to label adenosine receptor-related binding sites before more selective A2A tools were available.
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provided an initial pharmacological tool for receptor labeling before more selective ligands were available
Problem links
provided an initial pharmacological tool for receptor labeling before more selective ligands were available
LiteratureIt provided an initial way to label adenosine receptor-related binding sites before more selective A2A tools were available.
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It provided an initial way to label adenosine receptor-related binding sites before more selective A2A tools were available.
Taxonomy & Function
Primary hierarchy
Technique Branch
Method: A concrete measurement method used to characterize an engineered system.
Mechanisms
agonist-receptor bindingnon-receptor bindingnon-selective adenosine receptor engagementradioligand bindingTechniques
Functional AssayTarget processes
No target processes tagged yet.
Implementation Constraints
cofactor dependency: cofactor requirement unknownencoding mode: genetically encodedimplementation constraint: context specific validationoperating role: sensor
Use requires radioligand binding assays and receptor-containing membrane preparations. The review indicates that interpretation also depends on whether non-receptor binding components are present.; interpretation is confounded by non-receptor binding proteins such as adenotin; not suitable for satisfactory direct characterization of platelet A2A receptors
It does not cleanly distinguish A2A receptor binding from non-receptor binding in platelet membranes. The review states that much of the observed binding is to non-receptor sites.; non-selective across adenosine receptor subtypes; binding in human platelet membranes does not agree with A2A receptor pharmacology; majority of binding in platelet membranes is described as non-receptor binding
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
Activation of platelet A2A receptors increases cyclic AMP accumulation and decreases platelet aggregation.
Adenotin is a low-affinity non-receptor binding protein that confounds membrane binding analyses of A2A receptors and precluded direct characterization in platelet membranes with earlier ligands.
A2A adenosine receptors are expressed in human peripheral blood cells including platelets, lymphocytes, and neutrophils and are linked to platelet antiaggregatory, neutrophil antiinflammatory, and immune-modulatory effects.
[3H]-CGS 21680 interacts with platelet A2A receptors but is unsatisfactory in human platelet membranes because it also labels low-affinity non-receptor sites; it becomes more adequate after purification that reduces adenotin interference.
[3H]-NECA is unsatisfactory for direct characterization of human platelet A2A receptors because much of its binding in platelet membranes is to non-receptor sites.
[3H]-XAC does not permit satisfactory A2A receptor binding studies because of high non-specific binding.
[3H]-SCH 58261 enabled satisfactory binding characterization of the A2A receptor subtype in human platelets and is presented as the first radioligand to do so.
Approval Evidence
1 source1 linked approval claimfirst-pass slug 3h-neca
The non-selective agonist NECA (A1, A2A, A2B, A3) was the first pharmacological tool to be used for labelling the A2A receptor in the rat brain but it was also found to bind to different affinity states and subtypes of adenosine receptors... the majority of the [3H]-NECA binding to human platelet membranes is to non-receptor sites.
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tool limitationsupports
[3H]-NECA is unsatisfactory for direct characterization of human platelet A2A receptors because much of its binding in platelet membranes is to non-receptor sites.
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Comparisons
Source-stated alternatives
The review contrasts it with [3H]-CGS 21680 and [3H]-SCH 58261. [3H]-SCH 58261 is presented as a more selective and satisfactory A2A characterization tool.
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The review contrasts it with [3H]-CGS 21680 and [3H]-SCH 58261. [3H]-SCH 58261 is presented as a more selective and satisfactory A2A characterization tool.
Source-backed strengths
historically important as an early labeling tool
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historically important as an early labeling tool
Compared with [3H]-CGS 21680
The review contrasts it with [3H]-CGS 21680 and [3H]-SCH 58261. [3H]-SCH 58261 is presented as a more selective and satisfactory A2A characterization tool.
Shared frame: source-stated alternative in extracted literature
Strengths here: historically important as an early labeling tool.
Relative tradeoffs: non-selective across adenosine receptor subtypes; binding in human platelet membranes does not agree with A2A receptor pharmacology; majority of binding in platelet membranes is described as non-receptor binding.
Source:
The review contrasts it with [3H]-CGS 21680 and [3H]-SCH 58261. [3H]-SCH 58261 is presented as a more selective and satisfactory A2A characterization tool.
Compared with [3H]-SCH 58261
The review contrasts it with [3H]-CGS 21680 and [3H]-SCH 58261. [3H]-SCH 58261 is presented as a more selective and satisfactory A2A characterization tool.
Shared frame: source-stated alternative in extracted literature
Strengths here: historically important as an early labeling tool.
Relative tradeoffs: non-selective across adenosine receptor subtypes; binding in human platelet membranes does not agree with A2A receptor pharmacology; majority of binding in platelet membranes is described as non-receptor binding.
Source:
The review contrasts it with [3H]-CGS 21680 and [3H]-SCH 58261. [3H]-SCH 58261 is presented as a more selective and satisfactory A2A characterization tool.
Ranked Citations
- 1.