Mar 06, 2025
Version 2
Tail Immersion Test V.2
- 1University of California, San Diego
- George Lab @ UCSDTech. support email: olgeorge@ucsd.edu
Protocol Citation: Lani Tieu, Brent Boomhower, Olivier George 2025. Tail Immersion Test . protocols.io https://dx.doi.org/10.17504/protocols.io.eq2ly3rzpgx9/v2Version created by Olivier George
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: July 24, 2020
Last Modified: March 06, 2025
Protocol Integer ID: 39685
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.
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.
- Keep a thermometer inside the beaker.
- Turn the machine on (power switch located on the rear of the machine). 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 begin heating the bath. The screen will 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 (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 the set point of the temperature inside the water bath.
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 home cage.