Background:

Bay-K-8644 (R)-(+)- is a calcium channel inhibitor. Bay-K-8644 (R)-(+)- inhibits Ba2+ currents (IBa) (IC50=975 nM).

(±)-Bay K 8644, a conventional racemic mixture of Bay K 8644, is widely used as an L-type Ca2+ channel agonist. Each optical isomer possesses opposite effects on IBa, Bay-K-8644 (R)-(+)- as an antagonist and S(-)-Bay K 8644 as an agonist. Bay-K-8644 (R)-(+)- inhibits Ba2+ currents (IBa) (IC50=975 nM). When Bay-K-8644 (R)-(+)- (0.5 μM) is applied, IBa is suppressed to 71±10% of control. In the presence of Bay-K-8644 (R)-(+)- (0.5 μM), additional application of forskolin and sodium nitroprusside (SNP) further inhibits IBa[1]. Bay-K-8644 (R)-(+)- is a calcium channel inhibitor[2].

参考文献:
[1]. Zhu HL, et al. Antagonistic actions of S(-)-Bay K 8644 on cyclic nucleotide-induced inhibition of voltage-dependent Ba(2+) currents in guinea pig gastric antrum. Naunyn Schmiedebergs Arch Pharmacol. 2008 Dec;378(6):609-15.
[2]. Sidaway P, et al. L-type Ca2+ channel sparklets revealed by TIRF microscopy in mouse urinary bladder smooth muscle. PLoS One. 2014 Apr 3;9(4):e93803.