Verapamil Inhibits TRESK (K2P18.1) Current in Trigeminal Ganglion Neurons Independently of the Blockade of Ca2+ Influx

Abstract

Tandem pore domain weak inward rectifier potassium channel (TWIK)-related spinal cord K+ (TRESK; K2P18.1) channel is the only member of the two-pore domain K+ (K2P) channel family that is activated by an increase in intracellular Ca2+ concentration ([Ca2+]i) and linked to migraines. This study was performed to identify the effect of verapamil, which is an L-type Ca2+ channel blocker and a prophylaxis for migraines, on the TRESK channel in trigeminal ganglion (TG) neurons, as well as in a heterologous system. Single-channel and whole-cell currents were recorded in TG neurons and HEK-293 cells transfected with mTRESK using patch-clamping techniques. In TG neurons, changes in [Ca2+]i were measured using the fluo-3-AM Ca2+ indicator. Verapamil, nifedipine, and NiCl2 inhibited the whole-cell currents in HEK-293 cells overexpressing mTRESK with IC50 values of 5.2, 54.3, and >100 μM, respectively. The inhibitory effect of verapamil on TRESK channel was also observed in excised patches. In TG neurons, verapamil (10 μM) inhibited TRESK channel activity by approximately 76%. The TRESK channel activity was not dependent on the presence of extracellular Ca2+. In addition, the inhibitory effect of verapamil on the TRESK channel remained despite the absence of extracellular Ca2+. These findings show that verapamil inhibits the TRESK current independently of the blockade of Ca2+ influx in TG neurons. Verapamil will be able to exert its pharmacological effects by modulating TRESK, as well as Ca2+ influx, in TG neurons in vitro. We suggest that verapamil could be used as an inhibitor for identifying TRESK channel in TG neurons.

Response mechanism of hypocrellin colorants biosynthesis by Shiraia bambusicola to elicitor PB90

“…To investigate the cells involved in mediating PB90 to induce hypocrellin synthetic signal molecule and pathways, understand the role of NO, Ca 2+ , hydroxyl radicals, H 2 O 2 , superoxide anion radical, and singlet oxygen in induction culture, various active oxygen scavengers and quenching agents were added to the culture solution. For example, glycerin (10 mM) can be used as hydroxyl radical quenching agent, histidine (10 mM) as a singlet oxygen quencher, superoxide dismutase (SOD, 160 units/mL) as superoxide anion radical quencher, and CAT (160 units/mL) as H 2 O 2 quencher (Ishikawa et al 2010; Du et al 2017), cPITO (50 mm mol/L) can be used as NO specific quenching agent, and verapamil (150 mg/L) can be used as Ca 2+ scavenger (Park et al 2018). Results as shown in Fig.…”

Chemically Modified Derivatives of the Activator Compound Cloxyquin Exert Inhibitory Effect on TRESK (K2P18.1) Background Potassium Channel

“…The examination of the role of TRESK in primary sensory neurons is impeded by the lack of specific modulators. Several pharmacological agents, including inorganic modulators as zinc or mercuric ion (Czirják and Enyedi, 2006); the natural compounds hydroxy-a-sanshool from Szechuan peppers (Bautista et al, 2008); and aristolochic acid from Aristolochiaceae plants (Veale and Mathie, 2016), approved medicines such as lamotrigine or verapamil (Kang et al, 2008;Park et al, 2018); and also the insecticide pyrethroids (Castellanos et al, 2018) were demonstrated to inhibit the TRESK current.…”

TRESK (K2P18.1) Background Potassium Channel Is Activated by Novel-Type Protein Kinase C via Dephosphorylation

“…Recently, it has been suggested that the frameshift-induced alternative translation initiation and the dominant negative effect of the truncated TRESK subunit on TREK-1 and TREK-2 channels are responsible for migraine pathogenesis (Royal et al, 2019). Although a highly selective TRESK inhibitor is not yet available, great efforts have been made to identify pharmacological compounds modulating this putative drug target (Czirják and Enyedi, 2006b;Bautista et al, 2008;Kang et al, 2008;Beltrán et al, 2013;Kim et al, 2013;Wright et al, 2013;Monteillier et al, 2016;Park et al, 2016;Veale and Mathie, 2016;Castellanos et al, 2018;Park et al, 2018).…”