ADInstruments Rodent Langendorff - Set Up & Priming Demonstration

Our step-by-step guide to setting up, priming, and calibrating the ADInstruments Rodents Langendorff System.

Our Head of Support, Mark de Reus, demonstrates how to prime the ADInstruments Rodent Langendorff System.
 

Step-by-step:

1. Setting up the glassware
2. Setting up the hardware
3. Priming the system
4. Calibrating the flow
 

Equipment Required:

ADInstruments Rodent Langendorff

 

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Setting up the glassware 

  1. Screw the three support rods into the base.
  2. Position the spill tray in the centre of the base.
  3. Attach the clamps to the perfusate reservoirs, ensuring that they are tight enough to prevent slipping.
  4. Attach the clamped reservoir to the stand using the stand clamps.
  5. Place the gas bubbler inside the perfusate reservoir.
  6. Attach the gas manifold to the stand using the stand clamp with the yellow screw. This is a teflon screw which will not damage the glass gas manifold.
  7. Attach the direct perfusion core to the stand using the supplied clamps. 
    1. The direct perfusion core has four ports at the base of the main chamber which can be fitted with either a lure fitting for connection to a pressure transducer, or a rubber septa which is ideal for applying a drug via a syringe.
  8. Attach the heart chamber below the direct perfusion core using the supplied clamps.
  9. The direct perfusion core is connect to the heart chamber by screwing the lid, which is attached to the bottom of the direct perfusion core, onto the heart chamber.

The Water Jacketing Circuit

The tubing for the water jacketing system runs from a heated water circulator through a wire adaptor, to the heart chamber, up into the direct perfusion core, through a wire adaptor, into the bottom ports of the perfusate reservoirs, then through another wire adaptor and back to the heated water circulator

Quick Tip: If it’s difficult to attack the tubing to the ports, dip the end in some water and it will slid into the port quite easily.

The Gas Circuit 

A gas tank is attached to a regulator, and then attached to the gas manifold through a wire adaptor. From there it goes through two further wire adaptors, one to each of the input ports on the gas bubblers.

The Perfusate Pathway 

The perfusate is held initially in the perfusate reservoirs. It moves out through the output ports of the perfusate reservoirs and through wire adaptors to a three-way tap (where you can select whether the perfusate should come from both reservoirs or just one) and into the pump, from there it is pumped up a wire adaptor to the direct perfusion core, through the coil and into the bubble trap.

When priming the system the perfusate overflow will be open and the perfusate can then run back down into the reservoirs through wire adaptors attached to the input ports of the gas bubblers.

When the system is in operation the overflow is closed, forcing the perfusate down into the aortic cannula. 

 

Related: Why we redesigned the Langendorff Apparatus >>
 

Setting up the hardware

Measuring Pressure

  1. A physiological pressure transducer is attached to one of the four ports of the direct perfusion core so that it is as close as possible to the perfusate going into the heart.
  2. The pressure transducer is connected to the bridge amp.
  3. Click here for information on calibrating your pressure transducer.

Connecting the units

  1. Connect the BNC T-piece to the back of the bridge amp. The other end will connect to the pressure input on the back of the STH pump controller.
  2. Attach the front end interface to the rear of the bridge amp.
  3. Connect the USB-C to the USB-C port on the front end interface, and the USB-C port on the PowerLab C.
  4. Connect the analog cable to the front end interface, and then attach the red connector to the end of the BNC T-piece. 

Connecting the STH Pump controller to the PowerLab C

  1. Attach the front end interface to the STH Pump Controller.
  2. Connect the analog cable to the front end interface, and the red connector to ‘flow output’ on the STH Pump Controller.
  3. Connect the USB-C to the USB-C slot on the front end interface, and the other end of the USB-C to a USB-C slot of the PowerLab C.
  4. Connect the peristaltic pump to the STH Pump Controller by using the supplied interface cable from the pump to the STH Pump Controller.


Learn more about the ADInstruments Rodent Langendorff Apparatus >>
 

Priming the system

Once the system is all set up it is time to prime.

  1. Ensure the perfusate overflow on the direct perfusion core is open.
  2. Turn on the pump and ensure there is enough flow.
  3. The perfusate will move through the connecting tubes of the system.
  4. Once the perfusate has reached the overflow and is moving through the overflow back into the reservoirs you can turn the overflow off and turn on the cannula. This will allow flow into the heart chamber.
  5. Once the system is fully primed you can turn off the pump and close the cannula. 

Priming the Transducer (to remove bubbles)

  1. Close the cannula.
  2. Open the transducer port.
  3. Close the transducer port.
  4. Open the cannula again.

Dealing with bubbles in any of the ports

  1. Repeat the process you used for the transducer.
  2. Close the cannula, open the port, close the port, and then open the cannula again.

This forces perfusate all the way through the port and eliminates any bubbles.

 

Calibrating the Flow

On the Langendorff Apparatus

  1. Open the cannula.
  2. Set the pump to ‘external’, this allows it to be controlled by the STH pump controller.
  3. Set the flow to zero by turning the flow nob counter-clockwise.
  4. Switch the ‘run’ switch on.
  5. Adjust the flow with the flow nob until you’re at the desired flow.
  6. Place a measuring cylinder under the open cannula and collect perfusate for exactly one minute. This will give you the flow rate per minute.

In LabChart Lightning

  1. In LabChart Lightning open the channel that the flow output of the STH Pump Controller is connected. 
  2. There will be two areas on this graph, one where the flow is at 0, and one where the flow was at your selected flow rate.
  3. Highlight an area of the graph that includes these two levels, then select the channel (likely called ‘Flow’) 
  4. This will bring up a pop-up window.
  5. Click the ‘…’ button in line with ‘units’.
  6. This will bring you to another page of the pop-up where you can input your calibration data.
  7. Within this pop-up select an area of your graph that shows the flow at zero and click ‘Set point 1’.
  8. This will insert 0.0 into the ‘Raw Value’ box of ‘Point 1’.
  9. Add ‘0’ to the corresponding ‘Converted Value’ box.
  10. Now select an area of your graph where the flow is constant at your higher flow rate and click ‘Set point 2’.
  11. This will again result in a value being added to the ‘Raw Value’ box. Enter the number of millilitres of perfusate collected in your measuring cylinder.
  12. In the unit dropdown select ‘mL/min’.
  13. Click ‘Apply’.

 

Learn more about the ADInstruments Rodent Langendorff Apparatus >>