Ussing System For electrophysiological investigation of epithelial transport ● Direct connect low-resistance electrodes ● Simplified operation, easy to control temperature and clean after use ● Luer type leak-free attachment of tubing and electrodes ● Recessed electrode ports to avoid air bubble formation ● Secure membrane holding by sharp stainless steel pins or O-ring Glass circulation reservoir #5210 Ussing Chamber EPITHELIAL PHYSIOLOGY ● Specialized chamber adapts cell culture insert (Costar Snapwell) for monolayer cell culture ● Chambers with rectangular openings for tubular tissues from small animals WPI’s Ussing System offers researchers a quick, effective means of making low-resistance electrical connections to the Ussing chamber without need of long agar bridges or Calomel half-cells. Ag/AgCl half-cells screw into short tubes which plug firmly into place in the chamber’s luer ports. These direct-connect electrodes eliminate the inconvenience and expense of Calomel half-cells in open liquids. The system includes one Ussing Chamber (eight sizes available), support stand, electrode kit, glass circulation reservoir (two sizes available), and a tubing start-up kit (25 feet of 0.375-in. tubing, 10 feet of 0.156-in. tubing, plus four male luer fittings, two compressor clamps, one Y-connector, and one clip). Sixteen possible system configurations are listed at right. Components are also available separately. (Preamplifier in photo not included.) Complete Ussing System includes stand, glass reservoir, electrodes, Ussing chamber and tubing (EVC3 preamp and post mounting kit not included—see page 18). Two small chambers with rectangular openings are designed for tubular tissue from small animals such as the mouse intestinal tract membrane (CHM6) and rat intestinal tract membrane (CHM7). The rectangular opening more closely matches the shape of the tissue than would a circular opening, significantly increasing the membrane area available for testing. The larger membrane area increases the transport rate of low permeability chemicals; it also reduces the electrical resistance of the system for easier current clamping. Ussing Chambers WPI’s classical Ussing Chambers are well established perfusion chambers that are easy to operate, easy to control temperature, and easy to clean after use. Hundreds of them are used daily by scientists in the field. Ussing Chambers are machined from solid acrylic with eight entry ports for fluid lines, electrodes, or agar bridges. For easy, leak-free attachment of tubing and electrodes, all eight ports are luer type. The four ports for voltage and current electrodes are recessed to prevent formation of air bubbles in the chamber. The fluid compartments in each side of the chamber are separated by the epithelial membrane being studied. Sharp stainless steel pins on one side of the chamber hold the membrane in position and mate with holes in the opposite chamber interface. (In the CHM4, tissue is held by an O-ring instead of pins.) The CHM5 chamber adapts the Costar Snapwell, a cell culture insert for monolayer cell culture, into WPI’s “classical” epithelial voltage clamp system. Until now, classical Ussing Chambers have not been widely used for monolayer cell culture inserts because most inserts have a very deep profile, limiting good fluid perfusion at the surface of the membrane — and limiting voltage electrodes from measuring the potential close to the surface of the membrane. CHM5 solves these problems: Perfusion fluid is introduced into the chamber at an angle so that it will flow directly to the surface of the membrane. The voltage electrode is also inserted into the chamber at an angle so as to reduce the distance between the surface of the membrane and the electrode. 84 UK: Tel: +44 (0)1462 424700 • wpiuk@wpi-europe.com Optional Drains Drains may be added to Ussing chambers to allow quick and complete evacuation of radioactive or toxic substances. To have drains added at the time of order, add a “D” to the part number (such as “USS1LD”); cost of the drain ($105 to $140) will be added to the cost of the chamber or system ordered. Cartridge Electrodes The Electrode Kit contains four voltage/current electrodes, plus four luer-tipped cartridges. Electrodes are threaded and screw securely into the end of each cartridge. The luer tip then plugs securely into the luer openings of the chamber. The cable from each electrode terminates with a 2 mm pin which may be plugged into EKV and EKC voltage/current clamps such as WPI’s Cartridge Electrodes DVC1000 or EVC-4000. The miniature electrode-gel cartridge is a small plastic tube with a male luer tip identical to those at the tip of hypodermic syringes. The tube may be filled with different gel materials; agar is commonly used but other gel materials may also be satisfactory. U.S. Patent No. 4,912,060 World Precision Instruments www.wpiinc.com Germany: Tel: +49 (0)30-6188845 • wpide@wpi-europe.com US: Tel: 941-371-1003 • sales@wpiinc.com