ABSTRACT
This chapter outlines three main experimental methods for achieving very rapid solution exchange at the surface of dissociated cells and outside-out membrane patches. These are piezo, outside-out patch, piezo, whole-cell, and solenoid valve, whole-cell. An outside-out membrane patch is pulled from a cell, then the patch electrode is lifted away from the tissue and its tip positioned in the control solution flow close to the interface with the test solution. Piezoelectric materials change shape in response to an applied voltage. Stacks are several piezoelectric transducers connected mechanically in series and electrically in parallel. The piezoelectric translator has an intrinsic capacitance which interacts with the series resistance to determine the time constant of the voltage rise at the translator. Piezoelectric translators work at high voltages, and tend to produce big electrical artifacts in electrophysiological recordings. The speed of translation is limited by the mass of the flow pipe mounted on the translator and by the maximum force the translator can generate.
