![]() ![]() Several reasons have been suggested for these failures. One well-known failure is that of the neurokinin-1 receptor antagonists (substance P). This debate focuses on the failure of the translation of basic science data into effective analgesics and has led to a re-examination of the utility of animal models of pain and behavioral measures for screening new potential analgesics. There has recently been significant debate over the most appropriate animal models of pain and which behavioral measures should be used. Further, since pain has significant impact on function and quality of life (see IOM Report on Pain), measures that reflect these more complicated consequences of pain in animals will also help improve our understanding of mechanisms and diseases. ![]() As pain is a multidimensional experience that includes a sensory experience of pain which can be dissociated from unpleasantness, it is useful to have measures that assess spontaneous pain behaviors, cortical processing and decision making, and physical activity levels (reviewed below). It is clear that other behavioral tests can also produce valuable information that may not be gained solely from reflexive tests. ![]() efficacy, potency, duration of action) of a broad spectrum of analgesics to reduce reflexive sensory responses in rodent models of acute nociception and chronic pain have demonstrated consistent correspondence to human analgesia. Further, over the last several decades, the pharmacological action (e.g. These have clearly proven useful in advancing our understanding of the physiological basis of nociception, identification of neurotransmitters, receptors, intracellular messengers, and genes involved in pain behaviors and better understanding of existing pharmacological and non-pharmacological pain treatments. Measures of reflexive behaviors such as withdrawal thresholds to noxious stimuli have been used for decades to examine mechanisms of pain. Similarly, measures of nociceptive behavior must not only detect pain-like responses, but should do so in a manner consistent with the clinical experience of pain. The most appropriate models, whether an injury, application of chemical agents, or other manipulations, should produce nociception by recapitulating the mechanisms of specific clinical conditions. Īnimal models of nociception have two important components: the method of insult and the subsequent end-point measurement. It has become increasingly clear that that pain is a heterogenous phenomenon that differs widely based on the affected tissue (skin, muscle, joint, viscera, etc.) and the mechanism of injury (thermal, mechanical, inflammatory, neuropathic, etc). Since then, there have been a large number of animal models of disease developed to better understand pain from a variety of disease states, both acute and chronic, and have proven useful in further advancing disease-specific questions and processes. Despite the prevalence and impact of pain, it is extremely difficult to treat, and few basic science advances have been effectively translated to the clinical setting over the last several decades.Īnimal models of nociception (pain) date back to the late 19 th century and have been crucial in our understanding of pain processes. Further, pain costs the United States half a trillion annually, measured in terms of health care usage, lost wages, and impact on quality of life. The Institute of Medicine reports that more than 100 million Americans experience chronic pain – more than heart disease, cancer and diabetes combined. Pain, both acute and chronic, remains a significant health problem despite tremendous progress in understanding of its basic mechanisms. ![]() In this review we discuss the common methods used for inducing each of the pain phenotypes related to clinical pain syndromes, as well as the main behavioral tests for assessing pain in each model. Outcome measures are designed to measure multiple parts of the pain experience including reflexive hyperalgesia measures, sensory and affective dimensions of pain and impact of pain on function and quality of life. Animal models of pain are designed to mimic distinct clinical diseases to better evaluate underlying mechanisms and potential treatments. A number of animal models have been developed, reflecting observations that pain phenotypes are mediated by distinct mechanisms. Because of this, studying intact animals allows the multidimensional nature of pain to be examined. It is built from information gathered by specialized pain receptors in tissue, modified by spinal and supraspinal mechanisms, and integrated into a discrete sensory experience with an emotional valence in the brain. Pain is ultimately a perceptual phenomenon. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |