Biology Reference
In-Depth Information
CHAPTER 7
Patch Clamp Methods for Studying
Calcium Channels
David L. Armstrong, Christian Erxleben, and Jody A. White
Membrane Signaling Group
Laboratory of Neurobiology
National Institute of Environmental Health Sciences
NIH, Durham, North Carolina, USA
Abstract
I. Introduction
II. Rationale
III. Methods
A. Assembling the Patch Clamp Rig
B. Making Pipettes
C. Making Seals
D. Making Recordings
IV. Materials
V. Discussion
VI. Summary
References
Abstract
The patch clamp technique, which was introduced by Neher and Sakmann and
their colleagues in 1981, has allowed electrophysiologists to record ion channel
activity from most mammalian cell types. When well-established precautions are
taken to minimize electrical and mechanical fluctuations, current transients as small
as 0.5 pA and as brief as 0.5 ms can be measured reliably in cell-attached patches of
plasmamembranewith a polished glass pipettewhen it forms a giga-ohmseal with the
membrane. Inmany cases, this is su
cient to watch individual channel proteins open
and close repeatedly in real time on metabolically intact cells. No other technique
currently provides a more precise or detailed view of the function and regulation of
calcium channel gating. If antibiotics are added to the pipette to permeabilize the
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