In vitro activity: ABT-639 is a new potent, peripherally acting, selective T-type Ca2+ channel blocker that blocks recombinant human T-type (Cav3.2) Ca2+ channels in a voltage-dependent fashion (IC50=2 μM) and attenuates low voltage-activated (LVA) currents in rat DRG neurons (IC50=8 μM). ABT-639 is significantly less active at other Ca2+ channels (e.g. Cav1.2 and Cav2.2) (IC50>30 mM). Following oral administration ABT-639 produced dose-dependent antinociception in a rat model of knee joint pain (ED50 = 2 mg/kg, p.o.). ABT-639 (10-100 mg/kg, p.o.) also increased tactile allodynia thresholds in multiple models of neuropathic pain (e.g. spinal nerve ligation, CCI, and vincristine-induced). [corrected]. ABT-639 did not attenuate hyperalgesia in inflammatory pain models induced by complete Freund's adjuvant or carrageenan. At higher doses (e.g. 100-300 mg/kg) ABT-639 did not significantly alter hemodynamic or psychomotor function. The antinociceptive profile of ABT-639 provides novel insights into the role of peripheral T-type (Ca(v)3.2) channels in chronic pain states.

Kinase Assay:

Cell Assay: ABT-639 blocks recombinant human T-type (Cav3.2) Ca2+ channels in a voltage-dependent fashion (IC50=2 μM) and attenuates low voltage-activated (LVA) currents in rat DRG neurons (IC50=8 μM). ABT-639 is significantly less active at other Ca2+ channels (e.g. Cav1.2 and Cav2.2) (IC50>30 mM). ABT-639 has high oral bioavailability (%F=73), low protein binding (88.9%) and a low brain:plasma ratio (0.05:1) in rodents. Following oral administration