Rat Tissue EasyMount Ussing Chamber System

The P2250 Ussing Chamber has a usable half chamber volume range is 2.0 - 7.0 ml (typical working volume 5 ml per chamber half). The P2252 holders for mounting tissue samples must be ordered separately. We recommend ordering 1 extra P2252 slider to streamline the mounting process.

The EM8-R Rat Tissue Ussing System Includes:

Quantity	Part Number
	Voltage/Current Clamp Parts
1	VCC MC8-8S voltage/current clamp with optiGain
8	DM-MC6 Input Modules with Dummy Membrane
	Chamber Parts
1	EM-RSYS-8 Chamber System
8	P2250 Chambers
8	P2020-S Electrode sets
8	P2024-40 Electrode Lead Sets
8	P2060 Air Valve Sets
8	P2250-Caps (chamber caps)
2	P2020-S Extra Electrode sets
3	P2023-100 electrode tips (100/bag)
	Software
1	Acquire & Analyze Data Acquisition package with DI-720P
	Accessories
16	FN15 Filling Needles
1	GWB1 Gas Washing Bottle (1 L)
1	TK-7 Tubing and Setup Kit

 

 

The chamber stand is common to all our chamber systems. The stand consists of an anodized aluminum heat block which holds spring-loaded "cradles" to hold the acrylic Ussing chambers in place and tight against the heat block. CAM levers on each cradle provide a mechanism to remove the pressure on the chambers when tissues are being mounted. Temperature is maintained in the chamber by water pumped from a regulated water bath through the heat block. Because each chamber is individually mounted and pressed against the heat block, temperature in each chamber is the same (unlike competing systems). Air is is used to both oxygenate the tissue and provide stirring in the chamber.

Adjustment of airflow is by a needle valve mounted on the chamber stand directly behind each tissue half. Caps placed on the top of each chamber prevent contamination by droplets ejected  from the chamber when air bubbles break the surface. Voltage-sensing and current-passing electrodes mounted into electrolyte gel-filled bridges are inserted into special ports in the front face of each chamber half with the voltage-sensing electrode being positioned closest to the tissue. A voltage may be generated across the epithelium as a consequence of ion selective channels in the membranes and active transport by the tissue. This voltage is sensed by the black Ag/AgCl electrodes and measured by the voltage clamp instrument. Current may be passed by the clamp instrument across the epithelium via the white electrodes. When this current is sufficient to exactly cancel the voltage generated by the epithelium, the epithelium is “short-circuited” and the current necessary to do this is the short-circuit current (Isc). When the solutions in the chamber compartments are essentially the same so there are no ion gradients, the Isc is a measure of the net active transport of ions across the epithelium.

 

Electrodes are connected by cables (P2024-40) to the input module (DM-MC6) which, in turn, connects to a voltage clamp module (MC-601) in the VCC MC8-8S instrument. The optiGain feature supplies switches for setting the current gain and fluid-resistance compensation range for all clamp modules from the front panel of the  instrument. For the P2250 chamber with P2252 slider the optimal setting is Gain-10 and FRC-10.

Once tissues are mounted in the chamber the Master Control section can be used to synchronously set the Function, Mode and Meter switches on all modules. When the Mode switch is set to REM (remote) the Acquire & Analyze Data Acquisition can be used to record tissue bioelectrics. ACQUIRE and ANALYZE (A&A III) runs in the Windows® environment to measure current, voltage, conductance and resistance from 1-32 tissues simultaneously.