Abstract
TREKโ1 is a mechanosensitive member of the twoโpore domain potassium channel family (2PK+) that is also sensitive to lipids, free fatty acids (including arachidonic acid), temperature, intracellular pH, and a range of clinically relevant compounds including volatile anaesthetics. TREKโ1 is known to be expressed at high levels in excitable tissues, such as the nervous system, the heart and smooth muscle, where it is believed to play a prominent role in controlling resting cell membrane potential and electrical excitability. In this report, we use RTโPCR, Western blotting and immunohistochemistry to confirm that human derived osteoblasts and MG63 cells express TREKโ1 mRNA and protein. In addition, we show gene expression of TREK2c and TRAAK channels. Furthermore, whole cell patch clamp electrophysiology demonstrates that these cells express a spontaneously active, outwardly rectifying potassium โbackground leakโ current that shares many similarities to TREKโ1. The outward current is largely insensitive to TEA and Ba^2+^, and is sensitive to application of lysophosphatidylcholine (LPC). In addition, blocking TREKโ1 channel activity is shown to upregulate bone cell proliferation. It is concluded that human osteoblasts functionally express TREKโ1 and that these channels contribute, at least in part, to the resting membrane potential of human osteoblast cells. We hypothesise a possible role for TREKโ1 in mechanotransduction, leading to bone remodelling. J. Cell. Physiol. ยฉ 2005 WileyโLiss, Inc.