A device for automated control of pipette internal pressure for patch-clamp recording

Formation of a high-resistance seal between the tip of a glass recording pipette and the membrane of the recorded cell is the crucial step in patch clamping, or whole cell recording with patch pipettes. Formation of the seal, and subsequent rupture of the membrane for whole cell recording, requires a specific sequence of changes in pipette internal hydrostatic pressure. Generating this sequence of pressure changes adds to the complexity of setting up, gaining proficiency, and performing experiments. Automation of routine pipette pressure manipulations would simplify seal formation, and benefit productivity. Here we describe a device that automates control of patch pipette internal pressure. Solenoid valves sequentially operated by manual switching, or external electronic control, automatically provide the necessary sequence of connections to the pipette interior. This greatly simplifies the operations performed to obtain membrane seals and whole cell recordings and improves standardization and reproducibility in patch recording.