Dual Channel Epithelial Voltage Clamp (50 V compliance)

Overview:

The EC-825A-V Dual Channel Epithelial Voltage Clamp (50 V compliance) is specifically designed for studies of epithelial transport and the electrical properties of tissue. The EC-825A-V features high common mode rejection, clamp speed selection, membrane resistance measurement circuitry, and a watertight headstage with model membrane.

The Single Channel EC-800-V, Low Voltage Model EC-800LV-V and the Dual Channel EC-825A-V Epithelial Voltage Clamps provide accurate measurements of transepithelial voltage, short circuit current, and membrane resistance. Important features include fluid resistance compensation, membrane resistance readout, choice of voltage compliance, and small water-tight preamp headstages. Operating modes include voltage clamp, current clamp, voltmeter, and resistance.

Studies with small tissue samples or monolayers in set-ups with low access resistance may not require high compliance. For these applications, models EC-800LV-V offers both a lower cost and a safer environment for the membrane.

Accessories:

• U2500Dual Self-Contained Ussing Chamber accessories are available for the EC-825A-V Dual Channel Epithelial Voltage Clamp amplifier
  • U2500/A Dual Self-Contained Ussing Chamber w/O-Ring Insert 3.8 mm
  • U2500/B Dual Self-Contained Ussing Chamber w/Pin Insert 3.8 mm
  • U2500/C Dual Self-Contained Ussing Chamber w/Slotted Insert 1.6x7 mm Six Pins
    
  • U2500/M Dual Self-Contained Ussing Chamber w/Millicell Insert 12 mm
  • U2500/S Dual Self-Contained Ussing Chamber w/Snapwell Insert 12 mm
  • U2500/T Dual Self-Contained Ussing Chamber w/Transwell Insert 6.5 mm

Included with:

• PL3508B78-V Dual Channel Epithelial Voltage Clamp System

Note: Please specify V=115 or V=220 mains power

Features:

• For studies of epithelial transport and the electrical properties of tissue
• Membrane Resistance Measurement Circuit
• Clamp Speed Selection
• Independent Voltage and Current Commands
• Watertight Headstage with Model Membrane

The EC-800-V, EC-800LV-V and EC-825A-V are state-of-the-art instruments with several unique and important design features offering more reliable recording and operator convenience.

High CMR:
Differential voltage recordings are made with very high common mode rejection providing accurate measurements free from the effects of common mode potential changes of a noisy environment.

Membrane Resistance Measurement:
Accurate resistance measurements are made with the membrane mounted in the chamber. This measurement is made using a low frequency 2 Hz bipolar signal to avoid polarization of the membrane (ideal for monolayers). Resistances up to 200 kΩ are displayed on the meter with push-button convenience.

Clamp Speed Selection:
Three clamp speeds provide optimum recording conditions for a variety of applications. In Fast mode, preparations with low access resistance(small tissues or monolayers) can be clamped with speeds as fast as 10µsec. Typical Ussing chambers with larger tissues will use Medium or Slow modes for stable, oscillation free clamping.

Commands:
Internal DC Command (Hold) control for both Voltage clamp and Current clamp modes.

Watertight Headstage with Model Membrane:
The small compact headstage can be located close to the measurement site to keep input leads short for reduced noise pick-up. The model membrane circuit simulates a preparation to provide convenient operational checks of the clamp. Internal circuits are protected against the invasion of corrosive saline solutions by a watertight seal.

Choice of Voltage Compliance:
The EC-800-V has a voltage compliance of ±120 V, the EC-825A-V has a voltage compliance of ±50 V and the low voltage model EC-800LV-V has a voltage compliance of ±15 V. The high voltage compliance of these instruments are important for studies of low resistance (leaky) epithelial cells and in applications in which long agar leads in the current passing circuit produce large voltage drops (which must be compensated). Additionally, the high compliance helps in charging large membrane capacitances typical of epithelial tissues, resulting in faster settling times and improved overall clamp performance.

External Control:
The clamp can be operated by an external programmer, lab timer or computer. Logic control of clamp mode and clamp command levels is possible as well as simultaneous mixing of external linear commands.

Onboard Timer Controller:
The dual channel EC-825A-V includes event timers (2) to provide cycle times and clamp durations up to 2000 seconds. Times are set with 2 digit thumb wheel switches and 4 position range switches. Once set, the timer will free run, eliminating the need for a computer or other external device to control the experiment.

Model EC-800LV-V (±15 Volt Compliance):
Studies with small tissue samples or monolayers in set-ups with low access resistance may not require high compliance. For these applications,models EC-800LV-V offers both a lower cost and a safer environment for the membrane.

Applications:

The Dual Channel Epithelial Voltage Clamp is designed to provide accurate measurements of transepithelial voltage, short circuit current, and membrane resistance in small tissue samples or monolayers.

For more information see the Ussing Chamber application page.

Specifications: