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 c ells, but the molecular mechanisms that couple membrane tension or deformat ion to channel activity (i.e., mechanotransduction) are not understood. The ability to measure the dynamics of the temporal relationship between the p ressure stimulus and the channel response is a key tool for gaining insight into mechanotransduction. Several laboratories have designed pressure clam ps, but these instruments are complex, costly, and not commercially availab le. This paper describes a simple and inexpensive system for applying fast pressure steps to a membrane patch. This system is easy to build and achiev es submillisecond 20% to 80% step response times on par with the fastest pr essure clamp described. Application to a stretch-activated nonselective cat ion channel in the kidney is used to demonstrate the system.