Ketanserin (Ketanserinum) is a quinazoline derivative and serotonin (5-hydroxytryptamine, 5HT) receptor subtype 2 (5-HTR2) antagonist with potential antihypertensive and antiplatelet activities. Following administration, ketanserin binds to and inhibits the signaling mediated by 5-HTR2, which inhibits serotonin-dependent vasoconstriction and platelet activation.

5-HT2C (human):100 nM(Ki), 5-HT2C (rat):50 nM(Ki), ERG current (human):0.11 μM, 5-HT2A:2.5 nM(Ki)

Ketanserin is dissolved in DMSO to produce a stock solution of 100 mM. Ketanserin stock is diluted in experimental solutions to achieve the final concentrations[1]. The established HEK 293 cell line stably expressing hERG channels is cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% foetal bovine serum, 400 μg/mL G418. The HEK 293 cell line stably expressing recombinant human cardiac KCNQ1/KCNE1 channel current (IKs) is maintained in DMEM containing 10% foetal bovine serum and 100 μg/mL hygromycin. Cells used for electrophysiology are seeded on a glass coverslip. The mutant hERG channels are constructed, and are transiently expressed in HEK 293 cells using 10 μL of Lipofectamine 2000 with 4 μg of hERG mutant cDNA in pCDNA3 vector[1].