BL-1249 produces a concentration-dependent membrane hyperpolarization of cultured human bladder myocytes, assessed as either a reduction in fluorescence of the voltage-sensitive dye bis-(1,2-dibutylbarbituric acid)trimethine oxonol (EC50 of 1.26 μM) or by direct electrophysiological measurement EC50 of 1.49 μM). BL-1249 produced a concentration-dependent hyperpolarization with an EC50 of 21.0 μM in human aortic smooth muscle cells.
In in vitro organ bath experiments, BL-1249 produces a concentration-dependent relaxation of 30 mM KCl-induced contractions in rat bladder strips (EC50 of 1.12 μM), yet has no effect on aortic strips up to the highest concentration tested (10 μM). The bladder relaxation produced by BL-1249 is partially blocked by Ba (1 and 10 mM).
BL-1249 is a selective agonist of the TREK subfamily when applied extracellularly, having preferential action on K2P2.1(TREK-1) and K2P10.1(TREK-2) over K2P4.1(TRAAK) and establish that its mechanism of action relies on gating at the selectivity filter C-type gate.