*3.4. TREK-1 Potassium Channels*

The primary function of the two-pore potassium (K2P) channels is to mediate K<sup>+</sup>-selective leak currents that regulate cell excitability through a hyperpolarized resting membrane potential [126]. Several members of the K2P channel family including TRESK, TRAAK/KCNK4, TASK, TREK, and THIK are intrinsically mechanosensitive, and all are expressed in the DRG [127,128]. K2P channels are well established regulators of primary afferent fibers excitability. Two kinds of high conductance Ca2+-activated K<sup>+</sup> (KCa) channels and TREK-1 channels (TWIK-related K<sup>+</sup> channels) have been identified as putative mechanotransduction channels [19,46,102,113,114,129–131]. Investigation of K2P ion channels in the mammalian tooth pulp and in the odontoblast membrane revealed TREK1 mRNA expression in human odontoblasts [58,77]. Consequently, TREK-1 channels when stretch-activated may participate in the signal transduction to afferent nerve endings.
