Jul 23, 2020
Version 1
Protocol for Electronic von Frey V.1
This protocol is a draft, published without a DOI.
- 1University of California, San Diego
Protocol Citation: Lani Tieu, Lauren Smith, Olivier George 2020. Protocol for Electronic von Frey. protocols.io https://protocols.io/view/protocol-for-electronic-von-frey-bh97j99n
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 07, 2020
Last Modified: July 23, 2020
Protocol Integer ID: 38943
Keywords: Von Frey, mechanical allodynia, hyperalgesia, rats,
Abstract
The electronic von Frey measures mechanical sensitivity and allodynia. This protocol outlines the procedure for assessing the mechanical sensitivity threshold in rats using the electronic von Frey.
Guidelines
- Environment during testing must be quiet to reduce animals' stress
- Clean the clear boxes and metal grid with quatricide in between each set of animals
Materials
- Electronic von Frey apparatus (Ugo Basile® Dynamic Plantar Aesthesiometer 37450)
- Elevated horizontal grid
- Clear rat enclosures
- Quatricide (cleaner)
- Paper towels
Before start
Let the rats acclimate to the experimental room in their home cages for 1 hour.
Electronic von Frey setup
Von Frey touch stimulator and machine
Von Frey Setup
Von Frey Setup
5m
5m
Remove metal grid and clear boxes off the elevated platform
Place touch stimulator on testing surface and remove the needle cap
Place the metal grid back on the legs making sure the grid does not touch the needle
Place the clear boxes back on top of the grid making sure the opaque sides are placed to prevent animals from seeing each other
Switch on the Ugo Basile® Dynamic Plantar Aesthesiometer 37450 machine
Power button located at the rear of machine
Press F4 ("ESC") once, then F1 twice ("OPR" then "TST" ) to display the testing screen
Testing screen
Testing
Testing
Remove the lid and carefully place one rat per clear box, then place the lids on
Note
- Up to 6 animals can be tested at once
- If the animals are weighing down the grid causing it to touch the needle, take out 1 or 2 animals and test less animals at a time and spread them evenly across the grid
- The touch stimulator should move across the surface freely without the needle touching the grid while testing a set of animals
Allow rats to habituate in the clear boxes for 10 minutes
Measure the left hind paw first, then the right hind paw for the first animal
Position the needle under the center of the hind paw, then press the button on the touch stimulator to begin the force measurement
Note
Make sure the needle goes through the net and actually touches the paw.
Black dots indicate testing area. Avoid the testing the pads (bumps).
When paw withdrawal occurs due to pain, the needle will retract and the force and time will display on the machine. Record these measurements.
Note
The animal must be still during the application of the needle tip.
Continue measuring each paw for one animal, move on to the next animal, and so on until you have completed all the animals in your group. That is Trial 1. Then move on to Trial 2, and Trial 3. Once you have 3 Trials you are done.
Note
If an animal is walking or moving not because of pain, move on to the next animal and come back to it later.
After testing is complete, return animals to home cages
Clean the clear boxes and grid before testing another set of animals.
Cleanup
Cleanup
Clean all parts of the electronic von Frey (boxes, grid, needle) and make sure to recap the delicate von Frey needle.