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A simplified up-down method (SUDO) for measuring mechanical nociception in rodents using von Frey filaments.

Bonin RP, Bories C, De Koninck Y - Mol Pain (2014)

Bottom Line: However, this method results in animals receiving a varying number of stimuli, which may lead to animals in different groups receiving different testing experiences that influences their later responses.We further refined the PWT calculation to allow the estimation of PWT directly from the behavioral response to the fifth stimulus, omitting the need for look-up tables.SUDO thus offers an accurate, fast and user-friendly replacement for the widely used up-down method of Chaplan et al.

View Article: PubMed Central - HTML - PubMed

Affiliation: Unité de neurosciences cellulaires et moléculaire, Centre de recherche de l'Institut universitaire en santé mentale de Québec, 2601 Chemin de la Canardière, Québec, QC G1J 2G3, Canada. yves.dekoninck@neuro.ulaval.ca.

ABSTRACT

Background: The measurement of mechanosensitivity is a key method for the study of pain in animal models. This is often accomplished with the use of von Frey filaments in an up-down testing paradigm. The up-down method described by Chaplan et al. (J Neurosci Methods 53:55-63, 1994) for mechanosensitivity testing in rodents remains one of the most widely used methods for measuring pain in animals. However, this method results in animals receiving a varying number of stimuli, which may lead to animals in different groups receiving different testing experiences that influences their later responses. To standardize the measurement of mechanosensitivity we developed a simplified up-down method (SUDO) for estimating paw withdrawal threshold (PWT) with von Frey filaments that uses a constant number of five stimuli per test. We further refined the PWT calculation to allow the estimation of PWT directly from the behavioral response to the fifth stimulus, omitting the need for look-up tables.

Results: The PWT estimates derived using SUDO strongly correlated (r > 0.96) with the PWT estimates determined with the conventional up-down method of Chaplan et al., and this correlation remained very strong across different levels of tester experience, different experimental conditions, and in tests from both mice and rats. The two testing methods also produced similar PWT estimates in prospective behavioral tests of mice at baseline and after induction of hyperalgesia by intraplantar capsaicin or complete Freund's adjuvant.

Conclusion: SUDO thus offers an accurate, fast and user-friendly replacement for the widely used up-down method of Chaplan et al.

Show MeSH
Mouse mechanosensitivity measured with von Frey filaments. (A) Illustration of the up-down von Frey testing paradigms described by Chaplan et al. [3] and the simplified up-down method (SUDO). (B) Frequency distribution of the paw withdrawal threshold (PWT) estimates calculated using the method of Chaplan et al., [3] for the mouse dataset that was analyzed (n = 1065). (C) Frequency distribution of the mouse PWT divided by experimenter to reveal data heterogeneity (beginner n = 318, intermediate n = 220, expert n = 527). (D) Frequency distribution of the total number of von Frey presentations (trials) per test.
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Figure 1: Mouse mechanosensitivity measured with von Frey filaments. (A) Illustration of the up-down von Frey testing paradigms described by Chaplan et al. [3] and the simplified up-down method (SUDO). (B) Frequency distribution of the paw withdrawal threshold (PWT) estimates calculated using the method of Chaplan et al., [3] for the mouse dataset that was analyzed (n = 1065). (C) Frequency distribution of the mouse PWT divided by experimenter to reveal data heterogeneity (beginner n = 318, intermediate n = 220, expert n = 527). (D) Frequency distribution of the total number of von Frey presentations (trials) per test.

Mentions: In up-down methods of testing, a lack of response to a filament dictates that the next higher filament is used in the following stimulation, while a positive response dictates the use of the next lower filament. In the up-down method described by Chaplan et al. [3], the number of von Frey presentations in each trial is ultimately determined by the number of filament presentations required to approach the PWT. In this case, the PWT is assumed to exist in the vicinity of a stimulus level where the animal first changes its response pattern: a negative response followed by a positive response or vice versa (Figure 1A). Once this threshold is approached, another four von Frey presentations are done according to up-down rules and the PWT is calculated by combining the value of the final von Frey filament used with an adjustment factor based on the response pattern of the animal [3].


A simplified up-down method (SUDO) for measuring mechanical nociception in rodents using von Frey filaments.

Bonin RP, Bories C, De Koninck Y - Mol Pain (2014)

Mouse mechanosensitivity measured with von Frey filaments. (A) Illustration of the up-down von Frey testing paradigms described by Chaplan et al. [3] and the simplified up-down method (SUDO). (B) Frequency distribution of the paw withdrawal threshold (PWT) estimates calculated using the method of Chaplan et al., [3] for the mouse dataset that was analyzed (n = 1065). (C) Frequency distribution of the mouse PWT divided by experimenter to reveal data heterogeneity (beginner n = 318, intermediate n = 220, expert n = 527). (D) Frequency distribution of the total number of von Frey presentations (trials) per test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4020614&req=5

Figure 1: Mouse mechanosensitivity measured with von Frey filaments. (A) Illustration of the up-down von Frey testing paradigms described by Chaplan et al. [3] and the simplified up-down method (SUDO). (B) Frequency distribution of the paw withdrawal threshold (PWT) estimates calculated using the method of Chaplan et al., [3] for the mouse dataset that was analyzed (n = 1065). (C) Frequency distribution of the mouse PWT divided by experimenter to reveal data heterogeneity (beginner n = 318, intermediate n = 220, expert n = 527). (D) Frequency distribution of the total number of von Frey presentations (trials) per test.
Mentions: In up-down methods of testing, a lack of response to a filament dictates that the next higher filament is used in the following stimulation, while a positive response dictates the use of the next lower filament. In the up-down method described by Chaplan et al. [3], the number of von Frey presentations in each trial is ultimately determined by the number of filament presentations required to approach the PWT. In this case, the PWT is assumed to exist in the vicinity of a stimulus level where the animal first changes its response pattern: a negative response followed by a positive response or vice versa (Figure 1A). Once this threshold is approached, another four von Frey presentations are done according to up-down rules and the PWT is calculated by combining the value of the final von Frey filament used with an adjustment factor based on the response pattern of the animal [3].

Bottom Line: However, this method results in animals receiving a varying number of stimuli, which may lead to animals in different groups receiving different testing experiences that influences their later responses.We further refined the PWT calculation to allow the estimation of PWT directly from the behavioral response to the fifth stimulus, omitting the need for look-up tables.SUDO thus offers an accurate, fast and user-friendly replacement for the widely used up-down method of Chaplan et al.

View Article: PubMed Central - HTML - PubMed

Affiliation: Unité de neurosciences cellulaires et moléculaire, Centre de recherche de l'Institut universitaire en santé mentale de Québec, 2601 Chemin de la Canardière, Québec, QC G1J 2G3, Canada. yves.dekoninck@neuro.ulaval.ca.

ABSTRACT

Background: The measurement of mechanosensitivity is a key method for the study of pain in animal models. This is often accomplished with the use of von Frey filaments in an up-down testing paradigm. The up-down method described by Chaplan et al. (J Neurosci Methods 53:55-63, 1994) for mechanosensitivity testing in rodents remains one of the most widely used methods for measuring pain in animals. However, this method results in animals receiving a varying number of stimuli, which may lead to animals in different groups receiving different testing experiences that influences their later responses. To standardize the measurement of mechanosensitivity we developed a simplified up-down method (SUDO) for estimating paw withdrawal threshold (PWT) with von Frey filaments that uses a constant number of five stimuli per test. We further refined the PWT calculation to allow the estimation of PWT directly from the behavioral response to the fifth stimulus, omitting the need for look-up tables.

Results: The PWT estimates derived using SUDO strongly correlated (r > 0.96) with the PWT estimates determined with the conventional up-down method of Chaplan et al., and this correlation remained very strong across different levels of tester experience, different experimental conditions, and in tests from both mice and rats. The two testing methods also produced similar PWT estimates in prospective behavioral tests of mice at baseline and after induction of hyperalgesia by intraplantar capsaicin or complete Freund's adjuvant.

Conclusion: SUDO thus offers an accurate, fast and user-friendly replacement for the widely used up-down method of Chaplan et al.

Show MeSH