NS 638 is an inhibitor of the N-type voltage-gated calcium channel Cav2.2 and CNS L-type calcium channels.1 It inhibits potassium-induced calcium uptake in chick cortical synaptosomes (IC50 = 3.4 ?M) and AMPA-induced GABA release from primary chick cortical neurons (IC50 = 4.3 ?M), effects that can be blocked by the N-type calcium channel inhibitor ω-conotoxin GVIA but not the L-type calcium channel inhibitor nifedipine . It also inhibits potassium-induced calcium level increases in primary chick cerebellar granule cells (IC50 = 3.4 ?M), an effect that can be blocked by nifedipine but not ω-conotoxin GVIA. NS 638 (50 mg/kg) reduces infarct volume in a mouse model of focal ischemia induced by middle cerebral artery occlusion (MCAO) but not in a gerbil model of global ischemia induced by bilateral carotid artery occlusion (BCAO).
1.M?ller, A., Christophersen, P., Drejer, J., et al.Pharmacological profile and anti-ischemic properties of the Ca2+-channel blocker NS-638Neurol. Res.17(5)353-360(1995)