| Assay Method Information | |
| | Cellular In Vitro Assay for Determining Vasopressin V2 Receptor Activity |
| Description: | The identification of agonists and antagonists of the V1a and V2 vasopressin receptors from humans, rats and dogs as well as the quantification of the activity of the compounds of the invention is carried out using recombinant cell lines. These cell lines originally derive from a hamster's ovary epithelial cell (Chinese Hamster Ovary, CHO K1, ATCC: American Type Culture Collection, Manassas, Va. 20108, USA). The test cell lines constitutively express the human, rat or dog V1a or V2 receptors. In case of the Gαq-coupled V1a receptors, cells are also stably transfected with a modified form of the calcium-sensitive photoproteins aequorin (human and rat V1a) or obelin (dog V1a), which, after reconstitution with the cofactor coelenterazine, emit light when there are increases in free calcium concentrations [Rizzuto R, Simpson A W, Brini M, Pozzan T, Nature 358, 325-327 (1992); Illarionov B A, Bondar V S, Illarionova V A, Vysotski E S, Gene 153 (2), 273-274 (1995)]. The resulting vasopressin receptor cells react to stimulation of the recombinantly expressed V1a receptors by intracellular release of calcium ions, which can be quantified by the resulting photoprotein luminescence. The Gs-coupled V2 receptors are stably transfected into cell lines expressing the gene for firefly luciferase under control of a CRE-responsible promoter. Activation of V2 receptors induces the activation of the CRE-responsive promoter via cAMP increase, thereby inducing the expression of firefly luciferase. The light emitted by photoproteins of V1a cell lines as well as the light emitted by firefly luciferase of V2 cell lines corresponds to the activation or inhibition of the respective vasopressin receptor. The bioluminescence of the cell lines is detected using a suitable luminometer [Milligan G, Marshall F, Rees S, Trends in Pharmacological Sciences 17, 235-237 (1996)].Vasopressin V1a Receptor Cell Lines:On the day before the assay, the cells are plated out in culture medium (DMEM/F12, 2% FCS, 2 mM glutamine, 10 mM HEPES, 5 μg/ml coelenterazine) in 384-well microtiter plates and kept in a cell incubator (96% humidity, 5% v/v CO2, 37° C.). On the day of the assay, test compounds in various concentrations are placed for 10 minutes in the wells of the microtiter plate before the agonist [Arg8]-vasopressin at EC50 concentration is added. The resulting light signal is measured immediately in the luminometer. |
| Affinity data for this assay | |
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