Rapid pressure driven exocytosis-endocytosis cycle in a single plant cell. Capacitance measurements in aleurone protoplasts

The whole-cell patch-clamp technique has been used to increase intracellular pressure via the pipette while monitoring changes in membrane capacitance (related to membrane area) in single aleurone protoplasts. Increased pressure increased membrane capacitance and diameter, upon the release of pressure both parameters returned to resting levels. Pressure also reversibly increased membrane conductance. Comparison between diameter and capacitance shows that the capacitance changes are due to changes in cell surface area. These results show that pressure can rapidly alter the balance between exo- and endocytosis. Pressure-induced changes in conductance are suggested to be due to insertion/withdrawal of channels with the exo-/endocytosed membrane.