Facilitated giga-seal formation with a just originated glass surface.
A simple technique of tip preparation in patch pipettes is described, which facilitates giga-seal formation. The pipettes were fabricated from thick-walled borosilicate glass tubing (external diameter 2.0 mm, internal diameter 0.5 mm) and the tips could be repeatedly broken in the bath. The pipette resistance correspondingly fell in steps of 3-20 M omega from about 80 M omega to about 2 M omega (double concentrated Tyrode). Scanning electron microscopy showed that the tip obtained after breaking was fairly plain. These broken tips were especially appropriate for patch-clamping. In cardiac myocytes in 11 out of 26 patches with Na+ channel activity, giga-seals developed spontaneously, i.e. without suction. In these patches the amplitude of the mean current with depolarizing pulses to -40 mV was significantly higher in comparison with patches formed under negative pressure. It is concluded that spontaneously sealed patches are most likely of planar configuration and the Na+ channel activity exceeds that in suction-induced patches.
Institut für Vegetative Physiologie, Universität zu Köln, Germany.
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Benndorf
D000818:Animals; D005898:Glass; D006352:Heart Ventricles / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008855:Microscopy, Electron, Scanning; D018408:Patch-Clamp Techniques / Q000295:instrumentation*; D015222:Sodium Channels / Q000378:metabolism; D013499:Surface Properties
D015222:Sodium Channels