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Features ...
- Cm Compensation - with three time constants. Cm transients can be tuned out in the BATH before the current to voltage (I/V) converter, eliminating any chance for an amplifier stage to become saturated
- Leakage Resistance Compensation - Also done in the BATH before the I/V converter
- Series Resistance Compensation - Ten-turn calibrated dial
- Three Active Headstages (Vi, V1, V2) - Each with front panel controls for Offset, Capacity Compensation and Z Test that reads both on the Digital Meter and the 10V output BNC's
- Fourth Headstage (Bath/Guard) - Contains Voltage Clamp circuitry for Cut Open Guard compartment, output pin for Cm and Leakage Compensation, and also the Im current to voltage converter. There are eight front panel selectable Im gain ranges for the Bath/Guard Headstage [GAIN (a)], giving the actual current to voltage converter in the headstage ranges from 0.05mV/nA to 100mV/nA
- Processed Output Section: [GAIN (b)] - Adds additional gains of 1, 2, 5, 10, 20 or 50 to the Im signal
- Offset - Ten-turn dial allowing for a + 2 volt DC offset to be added to the Im signal
- Filter - Twelve-position four pole bessel low-pass filtering of Im signal
- Im Blanking - Two independent (CMOS 5 volt logic) back panel BNC inputs that blank the Im signal at the Bath/Guard Headstage
- Scope Trigger In/Out - Input Trigger signal from computer/stimulator is added to the internal Z Test and Clamp Test and sent to one Trigger output BNC
- Telegraph Outputs - Separate back panel telegraph output BNC's for Gain (a), Gain (b) and Filter settings
Modes of Operation:
TEV Mode
Conventional Two Electrode Clamp with 145 volt compliance and
three time constant Cm compensation. These capabilities are combined
with a very high performance bath clamp that enables you to clamp twice
as fast as any two electrode clamp available to date.
CUT-OPEN Mode (Mainframe)
A new unique Cut-open Oocyte Vaseline-gap method that is both very quiet, and is also fifty times faster (20 to 100 µs to change the membrane capacitance) than any oocyte clamp ever built. With this mode of operation, it is now also possible to control the intracellular milieu by internal perfusion of the oocyte. Now, stable recording lasting for several hours is possible. These properties allow the resolution of the time course of fast ionic and gating charge currents. Current noise is only about 1nA RMS at 3kHz bandwidth: a significant improvement over conventional two electrode oocyte clamps.
CUT-OPEN Mode (Headstage)
In this mode the Mainframe Clamp Amplifier is replaced by the Clamp Amplifier in the V1 Headstage. This eliminates much of the feedback path from V1 electrode (Voltage Monitoring) to I(Current Injecting) output. It improves speed and makes the CUT-OPEN operation even lower in noise (by a factor of 2 or 3 times!!)
The CA-1B is designed to be easy to use, yet provide excellent performance for the most demanding applications. The CA-1 was designed by Dr. Enrico Stefani in collaboration with Dr. Francisco Bezanilla, both with the UCLA School of Medicine. To view experimental data obtained by them using a CA-1, click here. In addition to the TEV mode, there have been many enhancements to Series Resistance compensation since publication of this technique. And now there is also a Processed Output Section.
Click here to view more illustrations
Temperature Control
The Cut-Open Chambers can also be temperature-controlled by using any of the three Dagan Temperature Controllers (TC-10, HCC-100A, or the DTC-200) along with the specially designed HE-104C Thermal Stage.
- HE-104C Thermal Stage for temperature controlled applications with recessed area for chamber (ie., CCP-2D-T). Is interchangeable with any Dagan Temperature Controller. See Temperature Control data sheet for more information.
- T Option By adding a 'T' to the end of the part number of any of the Cut Open chamber configurations, the main chamber is then made of a thermal-conductive material (ie., part #CCP-2D-T).
Cut Open Chamber Configurations and Accessories
- CC-1-P-LB or CC-1-T-LB
Basic Main Chamber . P for polycabonate or T for
temperature conductive Does not include boat set - CC-TG-ND Undrilled boat set (one small and one middle boat)
- HE-104C or HE-204C Temperature control stage to be used with Dagan TC-10 or HCC-100 heating/cooling controller.
- MS-104 Mounting Stage for non-temperature controlled applications. 3.6x3.8" plastic plate with six 8-32 threaded mounting holes and a recessed area for chamber.
- PL-6 A plastic block holding six Ag/AgCl pellets with six-inch wires and mating pins to the Bath/Guard Headstage. The plastic block has six wells for glass agar bridges that would then connect to the various chambers on the CC-1
