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Attention Score in Context
| Title |
Synthesis and Biological Evaluation of Thiophene-Based Cannabinoid Receptor Type 2 Radiotracers for PET Imaging
|
|---|---|
| Published in |
Frontiers in Neuroscience, July 2016
|
| DOI | 10.3389/fnins.2016.00350 |
| Pubmed ID | |
| Authors |
Ahmed Haider, Adrienne Müller Herde, Roger Slavik, Markus Weber, Claudia Mugnaini, Alessia Ligresti, Roger Schibli, Linjing Mu, Simon Mensah Ametamey |
| Abstract |
Over the past two decades, our understanding of the endocannabinoid system has greatly improved due to the wealth of results obtained from exploratory studies. Currently, two cannabinoid receptor subtypes have been well-characterized. The cannabinoid receptor type 1 (CB1) is widely expressed in the central nervous system, while the levels of the cannabinoid receptor type 2 (CB2) in the brain and spinal cord of healthy individuals are relatively low. However, recent studies demonstrated a CB2 upregulation on activated microglia upon neuroinflammation, an indicator of neurodegeneration. Our research group aims to develop a suitable positron emission tomography (PET) tracer to visualize the CB2 receptor in patients suffering from neurodegenerative diseases. Herein we report two novel thiophene-based (11)C-labeled PET ligands designated [(11)C]AAT-015 and [(11)C]AAT-778. The reference compounds were synthesized using Gewald reaction conditions to obtain the aminothiophene intermediates, followed by amide formation. Saponification of the esters provided their corresponding precursors. Binding affinity studies revealed Ki-values of 3.3 ± 0.5 nM (CB2) and 1.0 ± 0.2 μM (CB1) for AAT-015. AAT-778 showed similar Ki-values of 4.3 ± 0.7 nM (CB2) and 1.1 ± 0.1 μM (CB1). Radiosynthesis was carried out under basic conditions using [(11)C]iodomethane as methylating agent. After semi-preparative HPLC purification both radiolabeled compounds were obtained in 99% radiochemical purity and the radiochemical yields ranged from 12 to 37%. Specific activity was between 96 and 449 GBq/μmol for both tracers. In order to demonstrate CB2 specificity of [(11)C]AAT-015 and [(11)C]AAT-778, we carried out autoradiography studies using CB2-positive mouse/rat spleen tissues. The obtained results revealed unspecific binding in spleen tissue that was not blocked by an excess of CB2-specific ligand GW402833. For in vivo analysis, [(11)C]AAT-015 was administered to healthy rats via tail-vein injection. Evaluation of the CB2-positive spleen, however, showed no accumulation of the radiotracer. Despite the promising in vitro binding affinities, specific binding of [(11)C]AAT-015, and [(11)C]AAT-778 could not be demonstrated. |
X Demographics
The data shown below were collected from the profiles of 2 X users who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 2 | 100% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Members of the public | 2 | 100% |
Mendeley readers
The data shown below were compiled from readership statistics for 31 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 31 | 100% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Student > Ph. D. Student | 5 | 16% |
| Researcher | 4 | 13% |
| Student > Bachelor | 3 | 10% |
| Other | 3 | 10% |
| Professor | 2 | 6% |
| Other | 6 | 19% |
| Unknown | 8 | 26% |
| Readers by discipline | Count | As % |
|---|---|---|
| Chemistry | 7 | 23% |
| Medicine and Dentistry | 6 | 19% |
| Neuroscience | 4 | 13% |
| Agricultural and Biological Sciences | 2 | 6% |
| Immunology and Microbiology | 1 | 3% |
| Other | 2 | 6% |
| Unknown | 9 | 29% |
Attention Score in Context
This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 12 August 2016.
All research outputs
#20,655,488
of 25,371,288 outputs
Outputs from Frontiers in Neuroscience
#9,456
of 11,538 outputs
Outputs of similar age
#297,978
of 379,925 outputs
Outputs of similar age from Frontiers in Neuroscience
#124
of 147 outputs
Altmetric has tracked 25,371,288 research outputs across all sources so far. This one is in the 10th percentile – i.e., 10% of other outputs scored the same or lower than it.
So far Altmetric has tracked 11,538 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 10.9. This one is in the 12th percentile – i.e., 12% of its peers scored the same or lower than it.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 379,925 tracked outputs that were published within six weeks on either side of this one in any source. This one is in the 11th percentile – i.e., 11% of its contemporaries scored the same or lower than it.
We're also able to compare this research output to 147 others from the same source and published within six weeks on either side of this one. This one is in the 10th percentile – i.e., 10% of its contemporaries scored the same or lower than it.