Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular se...Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily （TRPV1, TRPV3, and TRPV4）, and finally members of the melastatin group （TRPM2, TRPM3, and TRPMS）. Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory com- pounds targeting specific pain/itch-TRPs so that physio- logical protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1- modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accom- plished via simple dosing strategies, and also by incorpo- rating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.展开更多
Chronic pain and itch are a pathological operation of the somatosensory system at the levels of primary sensory neurons, spinal cord and brain. Pain and itch are clearly distinct sensations, and recent studies have re...Chronic pain and itch are a pathological operation of the somatosensory system at the levels of primary sensory neurons, spinal cord and brain. Pain and itch are clearly distinct sensations, and recent studies have revealed the separate neuronal pathways that are involved in each sensation. However, the mechanisms by which these sensations turn into a pathological chronic state are poorly understood. A proposed mechanism underlying chronic pain and itch involves abnormal excitability in dorsal horn neurons in the spinal cord. Furthermore, an increasing body of evidence from models of chronic pain and itch has indicated that synaptic hyperexcitability in the spinal dorsal horn might not be a consequence simply of changes in neurons, but rather of multiple alterations in glial cells. Thus, understanding the key roles of glial cells may provide us with exciting insights into the mechanisms of chronicity of pain and itch, and lead to new targets for treating chronic pain and itch.展开更多
基金supported by the National Institutes of Health,USA(DE018549,UL1TR001117,P30AR066527,and AR48182 to WL,AR48182-S1 to WL as co-investigatorF33DE024668 and K12DE022793 to YC)+1 种基金the US Department of Defense(W81XWH-13-1-0299 to WL)the Harrington Discovery Institute,Cleveland OH(to WL)
文摘Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily （TRPV1, TRPV3, and TRPV4）, and finally members of the melastatin group （TRPM2, TRPM3, and TRPMS）. Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory com- pounds targeting specific pain/itch-TRPs so that physio- logical protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1- modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accom- plished via simple dosing strategies, and also by incorpo- rating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.
基金supported by JSPS KAKENHI Grant Numbers 15H02522the Core Research for Evolutional Science and Technology(CREST)program+3 种基金the Practical Research Project for Allergic Diseases and Immunology(Research on Allergic Diseases and Immunology)from Japan Agency for Medical Research and Developmentthe Toray Science FoundationTakeda Science FoundationThe Nakatomi Foundation
文摘Chronic pain and itch are a pathological operation of the somatosensory system at the levels of primary sensory neurons, spinal cord and brain. Pain and itch are clearly distinct sensations, and recent studies have revealed the separate neuronal pathways that are involved in each sensation. However, the mechanisms by which these sensations turn into a pathological chronic state are poorly understood. A proposed mechanism underlying chronic pain and itch involves abnormal excitability in dorsal horn neurons in the spinal cord. Furthermore, an increasing body of evidence from models of chronic pain and itch has indicated that synaptic hyperexcitability in the spinal dorsal horn might not be a consequence simply of changes in neurons, but rather of multiple alterations in glial cells. Thus, understanding the key roles of glial cells may provide us with exciting insights into the mechanisms of chronicity of pain and itch, and lead to new targets for treating chronic pain and itch.
