Adapters for combined intrapipette pressure pulses and patch pipette step movements during 'blind' cell search in brain slices

A procedure is described for 'blind' cell search in brain slices based on pressure pulses instead of steady-state pressure applied to the patch pipette during its stepwise movements. For reproducibility of the pressure/movement pattern during the cell search, we have developed two adapters, one for electrically and the other for hydraulically driven micromanipulators which generate pressure pulses synchronized with patch-pipette step movements. Both adapters increase the intrapipette pressure prior to a step movement of the pipette, maintain the pressure during the pipette movement, and release it between steps, thus minimizing the possibility of 'blowing-away' the cells during the search. The hydraulic micromanipulator adapter converts this into a stepping one. Both adapters also allow simultaneous recording of pipette step movements and of intrapipette pressure. The use of these adapters allows standardization of the 'blind' cell search and greatly increases the success rate of cells detection.