TTA-A2 is a potent, selective and orally active t-type voltage gated calcium channel antagonist with reduced pregnane X receptor (PXR) activation. TTA-A2 is equally potent against the Cav3.1 (a1G) and Cav3.2 (a1H) channels with IC50 values of 89 nM and 92 nM, respectively, at -80 and -100 mV holding potentials. TTA-A2 can be used for the research of a variety of human neurological diseases, including sleep disorders and epilepsy[1][2].
TTA-A2 exhibits a state-dependent inhibition of α1I with potencies of 98 nM and 3.7 μM at membrane holding potentials of -80 and -100 mV, respectively in astandard voltage-clamp electrophysiology assay. It also exhibits excellent selectivity against the Cav1.2 (L-type), Cav2.1 (P/Q-type), Cav2.2 (N-type), and Cav2.3 (R-type) channels which all had IC50 values of >30 μM at 80 mV[1].TTA-A2 exhibits high affinity in the α1I binding assay with a Ki of 1.2 nM and has excellent selectivity over the hERG potassium channel and L-type calcium channel (both IC50>10 μM)[1].
TTA-A2 (oral gavage; 3 mg/kg; single dose) produces significant changes in sleep architecture in rats. A reduction in active wake soon after dosing with a concurrent increase in delta sleep and decrease in REM sleep. Additionally, these effects persists for up to 4 h post-dose in rats[1].TTA-A2 (oral gavage; 10 mg/kg; once daily; 5 days) shows selective effect on recurrent thalamocortical network activity, it suppresses active wake and promotes slow-wave sleep in wild-type mice but not in mice lacking both Cav3.1 and Cav3.3[2]. Animal Model: Wild-type and double Cav3.1/Cav3.3 knockout C57BL6/Sv129 background mices[2]
[1]. Thomas S Reger, et al.Pyridyl amides as potent inhibitors of T-type [2]. Richard L Kraus, et al.In vitro characterization of T-type calcium channel antagonist TTA-A2 and in vivo effects on arousal in mice. J Pharmacol Exp Ther. 2010 Nov;335(2):409-17.