At PsychoGenics, we specialize in measuring compound-target engagement through in vivo and ex vivo receptor occupancy (RO) services. By utilizing selective radioligands and receptor autoradiography, we provide clear and actionable data. Moreover, our receptor autoradiography capabilities help determine tissue distributions of the target of interest and acquire Ki values through displacement assays on brain slices.  

Advanced Receptor Occupancy Technology

Harnessing the power of the BeaQuant system (ai4r, France), we’ve transformed traditional assessment practices. This revolutionary technology offers unparalleled high sensitivity (0.0005 cpm/mm2), enabling us to drastically cut down the time needed for specific binding assessment in the brain. With this system, results are achieved in mere hours, as opposed to the weeks required by traditional tritiated ligands. Such an efficient receptor occupancy research approach accelerates the study of compound-target interactions. It not only boosts speed and efficiency but also provides invaluable insights, allowing for more informed, earlier decisions. Furthermore, the speed and precision of the BeaQuant system makes receptor occupancy viable as a screening tool.

Receptor autoradiography offers a simple yet powerful way to determine the tissue distributions of target of interest and obtain Ki values by displacement assay on brain slices.

In ex vivo RO studies, only “cold” compounds are systemically administered. Autoradiographic binding of radioligand to brain slices of compound-treated animals is then quantified, and occupancy is measured as reduction in binding of radioligand.

When a suitable and selective radioligand that can cross blood-brain barrier is available, compound/target engagement by the test compound can be measured directly in vivo. This is achieved by systematic dosing the animal with the test compound followed by intravenous (tail injection) administration of a radioligand for the targeted receptor.

Options exist to perform in vivo RO studies without the need for radiolabeled materials and are therefore referred to “Cold” RO. Tracer molecules are still required, but the advantage of “cold” RO is that a wider selection of non-radiolabeled tracers may be available.

The 14C-2-DG autoradiographic method is instrumental in measuring glucose utilization correlating with cellular activity. It can help pinpoint brain regions activated by particular drug agents, making it a potential alternative to functional MRI. A key part of a CNS drug discovery strategy is to ensure that compounds identified in the screening cascade after peripheral administration are able to engage the target under investigation at relevant blood and brain/spinal cord concentrations. Radioligand-based receptor occupancy (RO) measurements, using methods such as in vivo/ex vivo autoradiography, is used to confirm the interaction of a drug with a specific biologic target, and to understand the relationship between dose, plasma, and brain exposures. It thus offers a powerful way to establish PK/PD relationships, and these assays have proved extremely useful in identifying novel CNS candidate compounds due to their high translational value when used to support clinical PET occupancy studies.

Collaborative Research Excellence for Your Next Breakthrough 

Leverage PsychoGenics’ expertise in preclinical receptor occupancy services to advance your research and drive breakthroughs in drug development in any therapeutic area. When combined with our suite of preclinical capabilities, our receptor occupancy analysis knowledge aids in drug dosing optimization, better target engagement understanding, and data-driven decision making for improved efficacy and safety. Count on PsychoGenics for consistent, reliable receptor occupancy insights. 

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