TEC-B-01 User Manual
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version 1.1
page 24
Compensate the potential offset (for both electrodes, see chapter 5.2), measure the electrode
resistance (for both electrodes, see chapter 5.3). The resistances should be 700 k
to 1-2 M
for
the potential electrode and 500 k
to 1 M
for the current electrode. As mentioned above, it is
usually not necessary to compensate for the electrode capacity (for the potential electrode, see
chapter 5.4).
Set the upper display to POTENTIAL ELECTRODE.
Insert the potential electrode into the oocyte. The potential electrode is inside the cell if you read a
membrane potential of about –50 mV to –60 mV. It’s a good idea to activate the audio monitor.
Then you can look through the microscope while hearing the membrane potential.
Remember
: The membrane potential of the oocyte is strongly dependent on the condition of the oocyte
(leaky or not), the experimental solutions and the membrane proteins (channels/transporters) that are
expressed.
If your reference electrode can be moved place it near the cell membrane and the potential
electrode to optimize differential potential recording (High Voltage TEC systems only).
Insert the current electrode into the oocyte. There are two indications that the current electrode is
inside the cell:
-
If you apply a test current pulse to the cell, the potential read by the potential electrode changes
according to Ohm’s law.
-
If you switch the POTENTIAL display to CURRENT ELECTRODE (see chapter 5.2) you read
the same membrane potential as read by the potential electrode.
After penetration with both electrodes the voltage responses of the cell to the test pulses in CC
mode should reflect the cell membrane resistance and time constant.
Start the experiment.
If you intend to work in VC mode tune the system in CC mode, then switch to VC mode and adjust
the clamp as described in chapter 5.6.
