RenaSci

Radioligand Receptor Binding Services

Receptor Binding Studies

 

RenaSci offers a variety of in vitro and ex vivo radioligand receptor binding assays for screening and characterising project compounds. These assays provide important information regarding the pharmacological profile of novel drugs at target receptors and uptake sites and binding sites associated with adverse side-effects such as sedation and drug abuse liability.


Our receptor binding services include off the shelf assays for well-characterised neurotransmitter receptors and uptake sites using commercially available [3H] radioligands. Examples are given below. We can also measure [3H]monoamine uptake into rat/mouse synaptosomes.

 

Table of Receptor Binding Assays

 

If your requirements are not on this list please enquire as we can easily set-up established binding assays for any other central receptor using commercially-available radioligands.


We also have considerable experience of novel assay development using custom-synthesised radioligands and can advise on the type of ligand to be labelled, the specific activity required for the binding assay and compounds that could be used to define non-specific binding. We would need a cell line expressing the target receptor or it would need to be expressed in a brain region in sufficiently high levels to enable assay development.


Experimental options :-


In vitro screening


•     Membrane preparations from cell lines or rat or mouse brain tissue

•     Displacements/inhibition constants (Kis)

•     Saturation studies to determine receptor affinity (Kd) and receptor density (Bmax)

 
Ex vivo receptor binding assays


•     Rats or mice (including genetically-modified animals)

•     Drugs given acutely or chronically by a variety of routes eg  po, ip, sc

•     Termination normally at time of peak effect

•     Optional blood/CSF or tissue sampling for PK

•     Tissue homogenates or brain slices (autoradiography)

•     Results expressed as mean specific binding and as a % of the control group (100%).

•     Parameters
          -   ED50 (dose of drug producing 50% displacement of the radioligand)
          -   Time course of receptor occupancy
          -   Receptor occupancy in different brain regions in the same animal
          -   Receptor occupancy at a range of molecular targets in the same animal

 

Ex vivo binding can be used to correlate central receptor occupancy with appropriate pharmacodynamic readouts to predict the mechanisms underlying observed in vivo responses and can be performed as an optional extra at the end of a study. We can also perform ex vivo binding on brain tissue from external studies.

 

High speed quantitative autoradiography


We employ Biospace BetaIMAGER™ systems to offer high speed quantitative autoradiography


Autoradiography Data

 

Key features of the Biospace BetaIMAGER™ technology are :-

 

•     Rapid measurement of specific binding in mouse or rat brain

•     Detection of tritium levels as low as 0.007 cpm/mm2

•     50 μM spatial resolution for accurate, reproducible results

•     Digital real-time imaging to optimise exposure time

 

We can perform complete ex vivo autoradiography studies using [3H], [125I] or other beta-emitting radioligands (please enquire). We also offer a read-only autoradiography service on clients own slides.

 

Autoradiography

 

Please contact us for further information about our in vitro and ex vivo receptor binding services.

 

Posters

 

Babbs et al. 2006 PSN S1 & PSN S2 are novel 5-HT1A agonists and norepinephrine reuptake inhibitors which show anti-feeding efficacy and superior cardiovascular safety to sibutramine in rats. Program No 62.3. Society for Neuroscience Meeting, Atlanta, Georgia, USA, 14th-18th October 2006.

 

Bennett et al. 2014 Pharmacology of mavoglurant, a metabotropic glutamate receptor 5 negative allosteric modulator. PB013. 5th BPS Focused Meeting on Cell Signalling, Leicester, UK, 28th-29th April 2014.

 

Cheetham et al. 2005. Ex vivo occupancy as a technique to assess drug actions at multiple targets. Program No. 447.6. Society for Neuroscience Meeting, Washington, DC, USA, 12th-16th November 2005.

 

Cheetham et al. 2008. Effect of the MCH1 antagonist, GW803430, on body weight, food and water intake, glucose tolerance, fat pad weight, ex vivo binding and various plasma parameters in dietary-induced obese C57BL/6J mice. Program No. 584.24. Society for Neuroscience Meeting, Washington, DC, USA, 15th-19th November 2008.

 

Heal et al. 2014. Binge-eating behaviour in rats induces changes in dopamine and opioid receptor binding in the brain. Poster Number M12. Presented at the 53rd Annual Meeting of the American College of Neuropsychopharmacology (ACNP), Phoenix, Arizona, USA, 7th-11th December 2014.

 

Henderson et al. 2011. Identification of the 5-HT6 antagonist AMR-SIX-1 for the treatment of obesity. Keystone Symposium, Obesity, Keystone, Colorado, USA, 12th-17th January 2011.

 

Viggers et al. 2008. Development and validation of a radioligand receptor binding assay for MCH1 receptors using [3H]AMR-MCH-1 in vitro and ex vivo. Program No. 584.27. Society for Neuroscience Meeting, Washington, DC, USA, 15th-19th November 2008.

 

Manuscripts


Heal et al. 2017. Dopamine and μ-opioid receptor dysregulation in the brains of binge-eating female rats - possible relevance in the psychopathology and treatment of binge-eating disorder. J. Psychopharmacol. 2017 Apr 1. doi: 10.1177/0269881117699607. [Epub ahead of print] [PubMed]


Watson et al. 2009. Receptor occupancy and brain free fraction. Drug Metab Dispos 37: 753-760. [PubMed]