Mechanosensitive potassium channels in locust muscle membrane

Patch clamp recordings have been made from adult locust (Schistocerca gregaria) muscle membrane to study the mechanosensitivity of potassium channels (BK and IK) in cell-attached patches by transiently applying measured pressures to the contents of the patch pipettes. The aim of the investigations was to demonstrate a novel gating behaviour by pressure of the BK channel in contrast to the familiar behaviour of the IK channel. The open probability (p^sub 0^) of the IK channel increased rapidly in response to a pressure step and monotonically during a pressure ramp. This gating was readily repeatable and rapidly reversible. The relationship between ln[p^sub 0^/(1-p^sub 0^)] and transmembrane pressure was linear. In comparison, p^sub 0^ for the BK channel was also increased by pressure, but its gating was delayed, cumulative, and hysteretic.[PUBLICATION ABSTRACT]