Patch-type pipettes increasingly are being used to obtain intracellula
r 'whole-cell' recordings from neurons. Here we describe our methods f
or making whole-cell recordings in vivo from midbrain neurons in an el
ectric fish. Novel elements in the procedure are: A device for micropo
sitioning the pipette when near a cell, use of a 'Picospritzer' for cl
eaning the pipette tip and cell surface, and an electroporetic method
for perforating the patch following seal formation. In addition, we sh
ow that extracellular and intracellular recordings can be made from th
e same neuron. Stable intracellular recordings can be made from neuron
s at least as small as 10 mu m.