Inhibitory Effect of Tricyclic Antidepressant Doxepin on Voltage-Dependent K+ Channels in Rabbit Coronary Arterial Smooth Muscle Cells.

Inhibitory Effect of Tricyclic Antidepressant Doxepin on Voltage-Dependent K+ Channels in Rabbit Coronary Arterial Smooth Muscle Cells. Cardiovasc Toxicol. 2019 Apr 27;: Authors: Li H, Kang H, An JR, Seo MS, Jung WK, Lee DS, Choi G, Yim MJ, Lee JM, Bae YM, Son YK, Choi IW, Park WS Abstract Doxepin, tricyclic antidepressant, is widely used for the treatment of depressive disorders. Our present study determined the inhibitory effect of doxepin on voltage-dependent K+ (Kv) channels in freshly isolated rabbit coronary arterial smooth muscle cells using a whole-cell patch clamp technique. Vascular Kv currents were inhibited by doxepin in a concentration-dependent manner, with a half-maximal inhibitory concentration (IC50) value of 6.52 ± 1.35 μM and a Hill coefficient of 0.72 ± 0.03. Doxepin did not change the steady-state activation curve or inactivation curve, suggesting that doxepin does not alter the gating properties of Kv channels. Application of train pulses (1 or 2 Hz) slightly reduced the amplitude of Kv currents. However, the inhibition of Kv channels by train pulses were not changed in the presence of doxepin. Pretreatment with Kv1.5 inhibitor, DPO-1, effectively reduced the doxepin-induced inhibition of the Kv current. However, pretreatment with Kv2.1 inhibitor (guangxitoxin) or Kv7 inhibitor (linopirdine) did not change the inhibitory effect of doxepin on Kv currents. Inhibition of Kv channels by doxepin caused v...
Source: Cardiovascular Toxicology - Category: Cardiology Authors: Tags: Cardiovasc Toxicol Source Type: research