Definition of Pain and Distress and Reporting Requirements for Laboratory Animals Proceedings of the Workshop Held June 22, 2000 (2000) / Chapter Skim
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Scientific Issues of Pain and Distress
Scientific Issues of Pain and Distress
Pages 22-30
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From page 22... ...
I also will raise the concept of preemptive strategies with respect to anticipation of postoperative pain. PAIN VERSUS NOCICEPTION Pain The widely accepted definition of pain was developed by a taxonomy task force of the International Association for the Study of Pain: "Pain is an unpleasant sensory and emotional experience that is associated with actual or potential tissue damage or described in such terms." A key feature of this definition is that it goes on to say, "pain is always subjective.
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From page 23... ...
and the information is conveyed along nerve axons to the spinal cord, a part of the central nervous system. Input from nociceptors is transferred in the spinal cord dorsal horn to spinal neuron cell bodies whose axons ascend to supraspinal (brain)
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From page 24... ...
Information from nociceptors is conveyed by sensory axons, whose cell bodies are in the dorsal root ganglion, to the spinal cord where they synapse onto second-order spinal cord neurons, which transmit the information to supraspinal sites (e.g., the thalamus in the brain)
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From page 25... ...
After tissue injury associated with inflammation and repair processes, the injured tissue exhibits enhanced sensitivity to stimulation, termed hyperalgesia (see text and Figure 3~. The enhanced sensitivity (e.g., to pressure applied to a sprained ankle or at the site of a surgical incision)
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From page 26... ...
If I were to test everyone in the audience with a thermal stimulus or a mechanical stimulus of varying intensity, as the intensity of the stimulus increased, each of us would report increasing pain sensation associated with increasing intensity of stimulation. This stimulus-response function can be shown to exist for individual central nervous system neurons; individual afferent fibers innervating skin, muscle, joints, or viscera; and the behavior of nociceptors.
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From page 27... ...
In this illustration, a noxious stimulus produces a pain sensation of approximately 25 in uninjured tissue. After tissue insult, that same intensity of stimulation produces significantly greater pain (approximately 55 on the arbitrary vertical scale)
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Bayne mentioned in the context of behavior. Stress is defined as the effect produced by external events or internal factors called stressors, which induce an alteration in an animal's biological equilibrium.
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From page 29... ...
Interestingly, that observation was made several years ago at an American Society of Anesthesiology meeting, when the big-breaking media point was preemptive analgesia. One of my technicians expressed surprise when she heard about it on the Today Show because her experiences with preemptive analgesia included having animals recover quietly and with less distress.
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From page 30... ...
If they are prolonged, obviously, and the animal then cannot adapt to those stressors in the environment and begins to develop maladaptive behaviors, I would agree that every one of those stressors could lead to distress. I would suggest that "negative effects" be more clearly defined in terms of behavior, specifically maladaptive behavior.
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