Source Paper
Methods Used to Evaluate Pain Behaviors in Rodents
Jennifer R. Deuis, Lucie S. Dvorakova, Irina Vetter
Frontiers in Molecular Neuroscience • 2017
View Abstract
Rodents are commonly used to study the pathophysiological mechanisms of pain as studies in humans may be difficult to perform and ethically limited. As pain cannot be directly measured in rodents, many methods that quantify "pain-like" behaviors or nociception have been developed. These behavioral methods can be divided into stimulus-evoked or non-stimulus evoked (spontaneous) nociception, based on whether or not application of an external stimulus is used to elicit a withdrawal response. Stimulus-evoked methods, which include manual and electronic von Frey, Randall-Selitto and the Hargreaves test, were the first to be developed and continue to be in widespread use. However, concerns over the clinical translatability of stimulus-evoked nociception in recent years has led to the development and increasing implementation of non-stimulus evoked methods, such as grimace scales, burrowing, weight bearing and gait analysis. This review article provides an overview, as well as discussion of the advantages and disadvantages of the most commonly used behavioral methods of stimulus-evoked and non-stimulus-evoked nociception used in rodents.
Randall-Selitto Test
Objective: Measurement of static mechanical hyperalgesia through application of pressure to skin or tissue to assess pain-like responses in rodents
Protocol Steps
Animal restraint
Restrain the rodent (mouse or rat) in preparation for testing
Note: Restraint is necessary to position the animal for pressure application
View evidence from paper
“The rodent is restrained and the hind paw (or tail) is placed between a pointed probe tip and flat surface.”
Position test site
Place the hind paw or tail between the pointed probe tip and flat surface of the Randall-Selitto device
Note: Either hind paw or tail can be used as the test site
View evidence from paper
“The rodent is restrained and the hind paw (or tail) is placed between a pointed probe tip and flat surface.”
Apply increasing pressure
Gradually increase the pressure applied by the device to the hind paw or tail
Note: Pressure is increased in a controlled manner until endpoint is reached
View evidence from paper
“The pressure is increased until withdrawal or vocalization occurs.”
Record endpoint
Record the pressure level at which the rodent exhibits withdrawal response or vocalization
Note: Endpoint is defined as either paw withdrawal or vocalization, whichever occurs first
View evidence from paper
“The pressure is increased until withdrawal or vocalization occurs.”