ABT-639 is a T-type calcium channel blocker. It inhibits inactivated-state Cav3.2 channels with an IC50 value of 2.3 μM and inactivated-state Cav3.1 and Cav3.3 channels by 50 and 39%, respectively, when used at a concentration of 10 μM. ABT-639 selectively inhibits inactivated-state T-type calcium currents over resting-state currents in rat dorsal root ganglion (DRG) neurons (IC50s = 7.6 and >30 μM, respectively). It reverses the hind limb grip force deficit in a rat model of osteoarthritic pain induced by monoiodoacetic acid (MIA; ED50 = 2 mg/kg). ABT-639 also increases the paw withdrawal threshold in rat spinal nerve ligation (SNL) and chronic constriction injury (CCI) models of neuropathic pain in a dose-dependent manner and attenuates cold allodynia in the CCI rat model when administered at doses greater than or equal to 3 mg/kg.
