Use of cryopreserved cells for enabling greater flexibility in compound profiling.

Measurement of intracellular calcium release following agonist challenge within cells expressing the relevant membrane protein is a commonly used format to derive structure-activity relationship (SAR) data within a compound profiling assay. The Fluorometric Imaging Plate Reader (FLIPR) has become the gold standard for this purpose. FLIPR traditionally uses cells that are maintained in continuous culture for compound profiling of iterative chemistry campaigns. This supply dictates that assays can only be run on 4 of 5 weekdays, or alternative cell culture machinery is required such that plating can occur remotely at the weekend. The data reported here demonstrate that high-quality compound profiling data can be generated from the use of cryopreserved cells and that these cells can also be plated at various densities to generate equivalent data between 24 and 72 h post-plating. Hence, the authors report a method that allows data generation throughout the week and without the requirement of highly automated cell culture or continuous culture.

Evidence for antagonist activity of the dopamine D3 receptor partial agonist, BP 897, at human dopamine D3 receptor.

The dopaminergic system has long been implicated in the mechanisms of reward and addiction. 1-(4-(2-Naphthoylamino)butyl)-4-(2-methoxyphenyl)-1A-piperazine HCl (BP 897) has been claimed to be a selective dopamine D3 receptor partial agonist and has recently been shown to inhibit cocaine-seeking behaviour, suggesting a role for dopamine D3 receptor agonists in the treatment of addiction. We have previously characterised the pharmacological profile of the human dopamine D3 and D2(long) receptors using microphysiometry and radioligand binding and we have now studied the interaction of BP 897 with the dopamine D2 and D3 receptors using these methods. At both human dopamine D3 and D2 receptors, BP 897 lacked agonist activity but was a potent and selective antagonist with pK(b) values of 8.05+/-0.16 (4) and 9.43+/-0.22 (4) at human dopamine D2 and D3 receptors, respectively. These results, therefore, suggest that it may be the dopamine D3 receptor antagonist properties of BP 897 which have potential in the treatment of addiction and withdrawal.