54
•
INSTRUMENT OPERATION
Axopatch 200B, Copyright 1997-1999, Axon Instruments, Inc.
Electrochemistry
The Axopatch 200B may be used to perform electrochemical measurements. Typically,
voltammetric experiments require a large command potential range in voltage-clamp mode.
This may be accomplished by setting the Holding Command toggle to "x5" for internal
commands and by using the 100 mV/V Rear-Switched external command input for external
commands. Similarly, amperommetric measurements may be made in one of the I-CLAMP
modes with the same command settings (in this case, to control the current instead of the
voltage).
For an introduction to electrochemical methods, you may refer to Kawagoe, Zimmerman
and Wightman, (1993) Journal of Neuroscience Methods 48: 225-240. Electrodes for
electrochemistry are available from Axon Instruments.
Headstage
The CV 203BU headstage incorporates several improvements over previous headstages.
The overall size is smaller and narrower than other headstages, allowing for greater ease of
placement during experiments. Three configuration choices (one patch and two whole-cell)
provide a wide useful range of operation. Most importantly, due to improved circuitry and
temperature control provided by an internal Peltier cooling unit, the CV 203BU offers the
lowest single-channel noise recording available. The critical headstage circuit components
are housed in a patented hybrid enclosure (U.S. Patent number 5,285,012), ensuring
consistent and reliable low-noise recording for years.
Offset Adjustment For Headstage
Headstage offsets drift slowly over time and, therefore, may require renulling every few
weeks. To do this, allow the headstage to warm up for a minimum of one hour. In
V-CLAMP mode, with PATCH mode selected and with open circuit input, adjust the rear
panel PATCH HEADSTAGE OFFSET potentiometer for a zero current reading on the
panel meter. Change to WHOLE CELL mode and adjust the rear panel WHOLE CELL
HEADSTAGE OFFSET for zero current.
To Next Page
Loading...
Need help?
General
