- Yasuda, O. et al. (1994) Artery 21, 287.
- Alomone Labs FS-2 inhibits CaV1.2 channels heterologously expressed in Xenopus oocytes. 1 µM FS-2 was also used to inhibit high K+ or glucose-induced L-type Ca2+ influx in RIN B insulinoma cells.Left: 500 nM FS-2 (#F-700) inhibits 50% of L-type CaV currents in Xenopus oocytes across the voltage range.
Right: Example traces of Ca2+ current responses to depolarization to +20 mV before and during application of FS-2.
FS-2 is a natural peptidyl toxin isolated from the Dendroaspis p. polylepsis black mamba venom by a modification of the procedure of Schweitz et al.1 and purified to homogenity. FS-2 is an L-type CaV channel blocker.2 The toxin reduced (±)Bay K8644-induced [Ca2+]in increase, in smooth muscle cells as determined by Ca2+ imaging with Fura-2.2 The IC50 for this effect was 23 nM.
FS-2 induced relaxation in pre-constricted rat aorta, pulmonary artery and trachea.3 In addition, it inhibited acetylcholine-induced contractions in guinea pig ileum.