Guide to Electrophysiological Recording
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patch technique, a rise in whole-cell capacity transients will be observed as the
compound partitions into the cell, as shown in Figure 4.3. The Membrane Test
feature of Clampex (v. 7 and higher) allows graphically monitoring the gradual rise
in capacitance (and decrease in Rs) as pores are formed in the patch membrane.
400 pA
3 ms
1 MIN
2 MIN
3 MIN
4 MIN
5 MIN
Figure 4.3.
Going whole-cell: capacity transients observed during amphotericin partitioning.
Low Noise Techniques
The MultiClamp 700B is capable of producing stable, low-noise recordings.
To
realize this performance the user must pay close attention to other sources of
noise.
This is because the total rms noise of a patch clamp recording is the square
root of the sum of the individual squared rms noise sources. This means that any
particular noise source that is large will dominate the total noise and make other
noise sources insignificant. Therefore, all potentially contributing noise sources
must be minimized. Specifically, the headstage, the pipette glass, the holder, and
Chapter 4
