RT Journal Article SR Electronic T1 Mechanical Activation of Piezo1 but not Nav1.2 Channels by Ultrasound JF bioRxiv FD Cold Spring Harbor Laboratory SP 136994 DO 10.1101/136994 A1 Martin Loynaz Prieto A1 Kamyar Firouzi A1 Butrus T. Khuri-Yakub A1 Merritt Maduke YR 2017 UL http://biorxiv.org/content/early/2017/06/06/136994.abstract AB Ultrasound can modulate the electrical activity of the brain and other excitable tissues but the mechanisms underlying this effect are not understood, either at the molecular level or in terms of the physical modality through which ultrasound exerts its effects. An obvious approach to address this question would be to measure ultrasound’s effects on specific candidate ion channels using patch-clamp recording, but ultrasound at the most commonly used frequencies permanently damages the gigaOhm seals required for patch-clamp recording. Here we report an experimental system that allows for stable patch-clamp recording in the presence of ultrasound at 43 MHz, a frequency known to stimulate neural activity in tissue in vitro. We describe the effects of ultrasound on two ion channels proposed to be involved in the response of excitable cells to ultrasound: the mechanosensitive Piezo1 channel and the voltage-gated sodium channel Nav1.2. Our patch-clamp recordings, together with finite-element simulations of acoustic field parameters indicate that Piezo1 channels can be activated by ultrasound through cell membrane stress and that acoustic streaming is required for this effect. Despite the reported sensitivity of voltage-gated sodium channels to membrane stress, Nav1.2 channels were not affected through this mechanism, but their activation and inactivation rates could be accelerated by ultrasound-induced heating. The approach described here will be useful in exploring the effects of different ultrasound modalities on ion channels, to better understand the endogenous response of excitable tissues to ultrasound and to help design ultrasound-sensitive channels for “sonogenetic” manipulation of cell activity.SIGNIFICANCE STATEMENT Ultrasound can both potentiate and inhibit electrical activity in the brain and other excitable tissues. This effect could potentially be exploited in the treatment of a wide variety of neurological and other diseases and disorders. To help guide the development of this exciting new technology, we sought to understand the mechanism of ultrasound’s effects on excitability. It has been hypothesized that mechanical forces associated with a propagating acoustic wave cause cell membrane stress, activating mechanosensitive ion channels, but approaches for testing this hypothesis have been limited, and thus evidence has been lacking. Here we develop a patch-clamp system for examining the effects of ultrasound on ion channels and show that ultrasound can indeed activate the mechanosensitive Piezo1 channel.