Jul 23, 2020
Version 1
Hot Water Tail Immersion Test V.1
This protocol is a draft, published without a DOI.
- 1University of California, San Diego
- George Lab @ UCSDTech. support email: olgeorge@ucsd.edu
Protocol Citation: Lani Tieu, Brent Boomhower, Olivier George 2020. Hot Water Tail Immersion Test . protocols.io https://protocols.io/view/hot-water-tail-immersion-test-bhxbj7in
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: June 25, 2020
Last Modified: July 23, 2020
Protocol Integer ID: 38595
Keywords: tail immersion, tail flick, rats, thermal nociception,
Abstract
The tail immersion test measures pain response (tail flick latency) to thermal stimuli, and can be used to evaluate the effectiveness of and tolerance to analgesics (e.g. oxycodone).
Guidelines
2 people (i.e. a dipper and a timer) are required to perform this test. Each timepoint that this test is performed must be done by the same people.
Note
A third person is needed for the drug onboard procedure.
Materials
MATERIALS
Water
- Water bath (Fisherbrand™ Isotemp™ GPD 02 Water Bath)
- 1000 mL beaker
- Thermometer
- Towel or pee pad
- Stopwatch
Before start
Set up water bath:
- Fill approximately one-third of the Fisherbrand™ Isotemp™ GPD 02 Water Bath machine with water.
- Fill beaker with approximately 900 mL water, then place beaker inside the water bath with the thermometer inside the beaker.
- Place the power switch located on the rear of the machine in the I position. The home screen will appear displaying the set point of the water temperature which should be 54°C.
- Press the power button on the front of the machine to turn start the bath and display the actual water temperature in the machine. Allow time for the temperature inside the beaker to reach 52°C before beginning experiment.
Note
The set point will heat the water inside the beaker to the desired temperature for this experiment which is 52°C. Maintaining 52°C inside the beaker is critical, so keep track of this temperature by checking the thermometer frequently throughout the experiment.
Set up of water bath. Display screen shows set point of the fluid temperature in the resevoir.
General Procedure
General Procedure
Pick up rat from its home cage and wrap it in a towel or pee pad to restrain it, leaving tail exposed.
The dipper will hold the restrained animal over the water bath and count down before dipping 1 cm of the distal tail into the water. As soon as the tip of the tail is submerged, the timer will start the stopwatch to begin timing the rat's tail flick latency.
Note
Animal must be relaxed with its tail being straight and still before immersing it in the bath.
As soon as tail flick reflex is observed, the timer will stop the stopwatch and record the tail flick latency.
Note
Tail flick reflex is indicated as animal attempting to withdraw its tail from the water (i.e. flicking the tip of its tail up).
Note
Do not allow more than 10 seconds to pass without observing a tail flick. Finish the procedure and record the time as 10 seconds to avoid tail damage.
Dry the rat's tail and return it back to its cage.
Drug Onboard Procedure (for IV oxycodone studies in rats)
Drug Onboard Procedure (for IV oxycodone studies in rats)
Inject 6 animals with 0.3 ml oxycodone (0.15 mg/kg) via the IV catheter.
Begin a stopwatch upon infusion of the first animal:
- Every 5 minutes, inject another 6 animals as in Step 1 and repeat this step for all animals
- After 15 minutes, begin the above tail immersion procedure for the first 6 animals in the order of drug infusion
Perform tail immersion procedure on each successive set of animals every 5 minutes.
Note
Work efficiently! 5 minutes should be just enough time to complete testing for each set of animals.