The ML870B76-V Oocyte Clamp Workstation System is designed for two-electrode, whole-cell voltage clamping of Xenopus Oocytes using the TEV700-V
Complete Oocyte Clamp Workstation.
System Components:
OC-725C-V Features:
- High compliance voltage (±180 V)
- Unique bath clamp circuitry
- Ideal for clamping large cells and cell structures, e.g. squid axons
- Extended current measuring range
- Decreased noise level and 4-pole Bessel filter
- An internal switch permits measurements of the current in series with the current electrode, instead of in the bath
- Optional differential voltage headstages
Fast Stable Voltage Clamping:
The OC-725C-V combines high AC and DC gains and a voltage compliance of ±180 V to ensure fast, non-saturating clamp performance under nearly any condition. The AC clamp gain is variable up to 2000. An additional DC gain of 1 x 106 may be employed for high conductance cells (leaky Oocytes).
Two clamp speeds are available:
The Slow mode is used for screening oocytes or for applications not requiring fast response times. The Fast mode is used for accurate voltage clamp of fast whole cell currents. Clamp response time in the Fast mode is 350 µsec (10-90% rise time) when applying a 100 mV step to a model cell.
Improved Bath Clamp Headstage:
The current measuring range of the OC-725C-V bath clamp headstage has been extended at both ends by the addition of a 3 position range multiplier. Smaller currents are amplified to usable levels and larger currents up to 1 mA can be recorded without output saturation. The unique design of the bath clamp eliminates the need for series resistance compensation. It provides an accurate measurement of bath current by creating a virtual ground in the bath while simultaneously clamping the bath potential at zero.
Voltage Headstage Probe:
The voltage measuring headstage is a single-ended, high-impedance probe. Its small size, convenient mounting rod and 2 meter cable make for easy attachment to a micropositioner. The headstage input is a 2 mm diameter pin. An electrode holder with a 2 mm jack (supplied) mounts directly on the headstage.
Voltage and Current meters:Independent meters provide simultaneous displays of membrane voltage Vm and membrane current Im. To assure proper impalement of the current electrode, the current meter displays membrane potential Ve from the current electrode before the clamp circuit is turned on.
Clamp Commands:
The internal Hold control is a digital push button control with two ranges; ±1 to 99 mV (x1) and ±2 to 198 mV (x2). Hold can be incremented in steps of 1, 2, 10 and 20 mV for I-V studies. External command signals applied to Command IN ÷10 are attenuated to reduce noise from the command source. Hold and external commands are summed.
Additional Features:
- Buzz controls (1 kHz square wave) for each electrode aid in penetration of cell membranes with a minimum of leakage
- Overload alarm (audible and visual) indicate when the compliance voltage is exceeded safeguarding the Oocyte and indicating that current records are subject to saturation
- DC Offsets for both voltage and current electrodes
- Electrode Test for both electrodes
- Capacity Compensation for the Vm voltage input
OC-725C-V Oocyte Clamp Amplifier Electrode Holders: Two vented electrode holders with silver wires are typically required with the clamp; a straight type for use with the voltage headstage and a 45° type with mounting handle for use with current electrodes. Vents have been added to the electrodes to prevent pressure build-up inside the electrode which can damage Oocytes. Typical electrode holder options are listed below.
- ESW-F10V Electrode Holder E Series Straight (1.0 mm capillary)
- ESW-F12V Electrode Holder E Series Straight (1.2 mm capillary)
- ESW-F15V Electrode Holder E Series Straight (1.5 mm capillary)
- ESW-F20V Electrode Holder E Series Straight (2.0 mm capillary)
- E45W-F10VH Electrode Holder E Series w/Handle 45° Style (1.0 mm capillary)
- E45W-F12VH Electrode Holder E Series w/Handle 45° Style (1.2 mm capillary)
- E45W-F15VH Electrode Holder E Series w/Handle 45° Style (1.5 mm capillary)
- E45W-F20VH Electrode Holder E Series w/Handle 45° Style (2.0 mm capillary
Dual Oocyte Studies: Some studies, such as voltage control across gap junctions, require the clamping of two oocytes in a common bath using two voltage clamps. The combined currents from the two Oocytes cause problems because the bath clamp headstage cannot separate the individual currents and therefore cannot provide effective clamping.
The OC-725C-V has two features to address these problems:
- An internal switch permits measurements of the current in series with the current electrode instead of in the bath
- Optional differential voltage headstages (Model 7255 DI): The differential measurement subtracts the voltage drop across the series resistance in the bath, which is normally eliminated by the bath clamp
Data Acquisition and Analysis:
The PowerLab 8/30 is shipped with ADInstruments software (LabChart and Scope), associated manuals and cables. The ML870/P is also supplied with LabChart Pro software which includes all the ADInstruments LabChart Modules (excluding GLP). LabChart Modules provide application specific data acquisition, analysis and display features.
The modules currently available include:
In purchasing this system containing LabChart Pro entitles the purchaser to 5 years of FREE LabChart Pro software upgrades and updates. Purchasers are also entitled to any ADInstruments modules released during this 5 year period (excludes GLP software).
For more information see the LabChart Pro page or contact your nearest ADInstruments representative.
Note: Please specify line operating voltage (V = 115 or 220 VAC)