For experiments involving the use of electrical stimulation, the ARC has developed the following parameters for pain categorization of animals.
For CONSCIOUS Animals
Guidelines for Single Electrical Stimulations
In order to list animals in Pain Category C (i.e., momentary or no pain/distress), the product of current in milliamps x duration in seconds from a constant current AC source must not exceed 5 millicoulombs for a single electrical stimulation. If this limit is exceeded, animals must be listed in Pain Category E (i.e., pain/distress cannot be relieved by use of anesthetics, analgesics, or tranquilizers, as the use of these agents would interfere with the experimental design). Scientific justification must be provided for exceeding 5 millicoulombs for a single stimulation. (see References for more information)
Guidelines for Repeated Electrical Stimulations
As a general guideline, animals must be listed in Pain Category E, with appropriate scientific justification provided as part of the research protocol, if more than 60 millicoulombs will be applied over the course of the animal’s lifetime. However, the ARC will use this threshold in combination with other factors in evaluating the most appropriate pain category for the animals. For example, animals may be placed in Pain Category E if the intent of the study is to create a model of persistent psychological distress or to induce localized tissue damage using lesser amounts of shock. Alternatively, animals that are allowed to voluntarily receive shock in order to gain access to an appetitive reward may be placed in Pain Category C even if the animal is permitted to self-administer a higher amount of shock.
For ANESTHETIZED Animals
Anesthetized animals subjected to electrical stimulation must be listed in Pain Category D (i.e., pain/distress relieved by use of appropriate anesthetics, analgesics, tranquilizers or by euthanasia) if the application of anesthesia is intended to alleviate pain or distress. Placement of animals in Pain Category E is appropriate if the stimulation procedures are expected to cause tissue damage resulting in pain that cannot be relieved upon recovery from anesthesia. Scientific justification must be provided for (1) the total amount of shock to be applied and (2) withholding analgesia or other pain-relieving drugs following recovery from anesthesia.
References
For a single electrical stimulation, no further increases in fear learning are observed beyond 5 millicoulombs. Fanselow, M.S. & Bolles, R.C. (1979) Naloxone and shock elicited freezing in the rat. Journal of Comparative & Physiological Psychology, 93, 736-744.
Muscle tetanizes at 7mA. The cut-off of 5mC is used to avoid reaching this level. Campbell, B.A., & Masterson, F.A. (1969). Psychophysics of punishment. In B.A. Campbell & R.M. Church (Eds.), Punishment and aversive behavior (pp. 3-42). New York: Appleton-Century-Crofts.
The limit for a single electrical stimulation was set to be below what produces learned helplessness, a long-term detrimental consequence that requires additional justification. Seligman M.E., Rosellini R.A., Kozak M.J. (1975) Learned helplessness in the rat: time course, immunization, and reversibility. Journal of Comparative & Physiological Psychology, 88(2):542-7.
Approved 6/11/01; Revised 1/11/10, 9/23/24