WPI - Model Duo 773 -Electrometer intracellular Amplifier

Benefits

• Dual channel, single ended recording
• Differential recording
• Bridge circuit nulls electrode voltage drop
• Assign low pass filter to either channel
• Very high impedance channel can be used with intracellular ISE

Applications

• Intracellular electrophysiology using sharp micropipettes
• Brain slice intracellular recording
• In vivo intracellular recording from brain and spinal cord

2-Channel intracellular amplifier for dual and differential studies

Headstage For Precise Positioning

For intracellular dual or differential studies, the Duo773 has separate negative capacity controls and built-in active filtering that allows the precise balancing of time constants for artifact-free differential measurement. Comes complete with two probe headstages, 10^15 Ohms & 10^11 Ohms probes to monitor signals from ion-specific micro-electrodes as well as KCl-filled electrodes. Two gold-plated, epoxy sealed miniature active probes can be positioned directly to the measurement site. Microelectrode holders containing an Ag/AgCl electrochemical half-cells plug directly into the probes. Stray capacitance can be reduced by placing the included driven guard shield over the microelectrode holder at the end of the probe.

Capacity Compensation

Channel A can compensate up to 10 pF of electrode shunt capacity and Channel B can compensate up to 50 pF.

Tickler Circuit For Penetration

A tickler circuit assists in cell penetration. The frequency and amplitude of the oscillations may be varied for differences in membrane thickness or cell size. The duration of tickle can be controlled either by using the momentary switch, a foot switch, or by applying a signal to the remote tickler input.

Active Filters

Low pass settings on a -40 dB/decade active filter vary the cutoff from 1 to 30 kHz. Either probe or bridge outputs may be selected for filtering.

Current Injection

Channel B can eject current through the microelectrode by applying a command signal to the stimulus input connector; the resulting output from the probe will then be a constant current replica of the input signal. Two ranges of current delivery are provided: 50 nA and 500 nA or by an external source. This source can be useful for delivering hyperpolarizing currents to stabilize the cell membrane potential and as a holding current for microiontophoresis.

Bridge Balance

Subtracts the excess electrode voltage associated with delivering current through the recording micropipette. Electrode resistances up to 1000 MΩ can be balanced in two ranges. The balanced signal is available from x10 or x50 front panel output connectors.

Independent Outputs

The Duo773 has an output for each probe independent of gain filtering or balancing. In addition the Duo773 has a 10x and a 50x output for easy integration to most data aquisition programs.