VCC 600 Physiologic Instruments Pulse Generator / Voltage-Current Clamp

The Physiologic Instruments VCC 600 Pulse Generator / Voltage-Current Clamp is designed to be a flexible tool for electrophysiological studies of ion transport by epithelial and other barrier tissues. It features an active headstage, user selectable current and fluid resistance compensation ranges, a pulse generator for conductance/resistance measurements, an interface for remote instrument control and data acquisition via computer, and large (0.5") LED readout. The VCC600 has been useful both for standard Ussing chamber experiments and, when combined with microelectrodes connected to an electrometer, for simultaneously studying transepithelial, transapical and transbasolateral membrane resistances and voltages and when combined with pH measurements for determining acid and base transport.

The single channel device is capable of controlling either the voltage or current across an epithelium. It is the most versatile instrument in the VCC series. Basic features include compensation controls with calibrated 10-turn dials for electrode offset voltage and fluid (series) resistance, user selectable ranges for current measurement gain, fluid resistance compensation and response frequency. A Clamp Level control allows a DC holding voltage or current to be set while a built-in pulse generator provides for applying unipolar or bipolar step changes in voltage or current from the holding level for tissue conductance/resistance measurements. Voltages and currents can be monitored via recorded outputs on the front panel and buy a bright 3.5-digit LED digital panel meter. An interface connector for a remote instrument control and data acquisition is provided on the rear panel. A high voltage option is also available to increase the output compliance voltage to +35 VDC for certain types of experiments.