TRPV1 Unlike TRPV2 Is Restricted to a Subset of Mechanically Insensitive Cutaneous Nociceptors Responding to Heat
| Autor: | Brian M. Davis, H. Richard Koerber, Sabrina L. McIlwrath, Jeffrey J. Lawson, C. Jeffery Woodbury |
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| Rok vydání: | 2008 |
| Předmět: |
Hot Temperature
Calcitonin Gene-Related Peptide Pain TRPV Cation Channels Sensory system Somatosensory system Nerve Fibers Myelinated Article Mice Organ Culture Techniques Cutaneous receptor Ganglia Spinal medicine Animals Thermosensing Neurons Afferent Skin Inflammation Mice Knockout Nerve Fibers Unmyelinated business.industry Nociceptors Anatomy Immunohistochemistry Sensory neuron Mice Inbred C57BL Disease Models Animal Anesthesiology and Pain Medicine medicine.anatomical_structure nervous system Neurology Hyperalgesia Receptive field Nociceptor Calcium Channels Neurology (clinical) medicine.symptom business Mechanoreceptors Neuroscience Transduction (physiology) |
| Zdroj: | The Journal of Pain. 9:298-308 |
| ISSN: | 1526-5900 |
| Popis: | In the present study, a murine ex vivo somatosensory system preparation was used to determine the response characteristics of cutaneous sensory neurons staining positively for TRPV1 or TRPV2. TRPV1 immunostaining was found exclusively (11/11) in a specific set of mechanically insensitive unmyelinated (C) nociceptors that responded to heating of their receptive fields. No cutaneous C-fibers that responded to both mechanical and heat stimuli stained positively for TRPV1 (0/62). The relationship between TRPV2 and heat transduction characteristics was not as clear, as few unmyelinated or myelinated fibers that responded to heat contained TRPV2. TRPV2 was found most frequently in mechanically sensitive myelinated fibers, including both low threshold and high threshold mechanoreceptors (nociceptors). Although TRPV2 was found in only 1 of 6 myelinated polymodal nociceptors, it was found in a majority (10/16) of myelinated mechanical nociceptors. Thus, whereas the in vivo role of TRPV1 as a heat-sensitive channel in cutaneous sensory neurons is clearly defined, the role of TRPV2 in cutaneous neurons remains unknown. These results also suggest that TRPV1 may be essential for heat transduction in a specific subset of mechanically insensitive cutaneous nociceptors and that this subset may constitute a discrete heat input pathway for inflammation-induced thermal pain. Perspective The distinct subset of murine cutaneous nociceptors containing TRPV1 has many attributes in common with mechanically insensitive C-fibers in humans that are believed to play a role in pathological pain states. Therefore, these murine fibers provide a clinically relevant animal model for further study of this group of cutaneous nociceptors. |
| Databáze: | OpenAIRE |
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