Application of pressure steps to mechanosensitive channels in membrane patches: a simple, economical, and fast system

Mechanosensitive channels (MSCs) have been described in a wide variety of cells, but the molecular mechanisms that couple membrane tension or deformation to channel activity (i.e., mechanotransduction) are not understood. The ability to measure the dynamics of the temporal relationship between the pressure stimulus and the channel response is a key tool for gaining insight into mechanotransduction. Several laboratories have designed pressure clamps, but these instruments are complex, costly, and not commercially available. This paper describes a simple and inexpensive system for applying fast pressure steps to a membrane patch. This system is easy to build and achieves submillisecond 20% to 80% step response times on par with the fastest pressure clamp described. Application to a stretch-activated non-selective cation channel in the kidney is used to demonstrate the system.