Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn.
Transient receptor potential melastatin 8 (TRPM8) ion channels mediate the detection of noxious and innocuous cold and are expressed by primary sensory neurons, but little is known about the processing of the TRPM8-mediated cold information within the trigeminal sensory nuclei (TSN) and the spinal d...
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doaj-21cd31da27b74ff39d56f639f36375062020-11-25T00:47:27ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0194e9408010.1371/journal.pone.0094080Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn.Yun Sook KimJun Hong ParkSu Jung ChoiJin Young BaeDong Kuk AhnDavid D McKemyYong Chul BaeTransient receptor potential melastatin 8 (TRPM8) ion channels mediate the detection of noxious and innocuous cold and are expressed by primary sensory neurons, but little is known about the processing of the TRPM8-mediated cold information within the trigeminal sensory nuclei (TSN) and the spinal dorsal horn (DH). To address this issue, we characterized TRPM8-positive (+) neurons in the trigeminal ganglion and investigated the distribution of TRPM8+ axons and terminals, and their synaptic organization in the TSN and in the DH using light and electron microscopic immunohistochemistry in transgenic mice expressing a genetically encoded axonal tracer in TRPM8+ neurons. TRPM8 was expressed in a fraction of small myelinated primary afferent fibers (23.7%) and unmyelinated fibers (76.3%), suggesting that TRPM8-mediated cold is conveyed via C and Aδ afferents. TRPM8+ axons were observed in all TSN, but at different densities in the dorsal and ventral areas of the rostral TSN, which dominantly receive sensory afferents from intra- and peri-oral structures and from the face, respectively. While synaptic boutons arising from Aδ and non-peptidergic C afferents usually receive many axoaxonic contacts and form complex synaptic arrangements, TRPM8+ boutons arising from afferents of the same classes of fibers showed a unique synaptic connectivity; simple synapses with one or two dendrites and sparse axoaxonic contacts. These findings suggest that TRPM8-mediated cold is conveyed via a specific subset of C and Aδ afferent neurons and is processed in a unique manner and differently in the TSN and DH.http://europepmc.org/articles/PMC3977991?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yun Sook Kim Jun Hong Park Su Jung Choi Jin Young Bae Dong Kuk Ahn David D McKemy Yong Chul Bae |
spellingShingle |
Yun Sook Kim Jun Hong Park Su Jung Choi Jin Young Bae Dong Kuk Ahn David D McKemy Yong Chul Bae Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. PLoS ONE |
author_facet |
Yun Sook Kim Jun Hong Park Su Jung Choi Jin Young Bae Dong Kuk Ahn David D McKemy Yong Chul Bae |
author_sort |
Yun Sook Kim |
title |
Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. |
title_short |
Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. |
title_full |
Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. |
title_fullStr |
Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. |
title_full_unstemmed |
Central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. |
title_sort |
central connectivity of transient receptor potential melastatin 8-expressing axons in the brain stem and spinal dorsal horn. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2014-01-01 |
description |
Transient receptor potential melastatin 8 (TRPM8) ion channels mediate the detection of noxious and innocuous cold and are expressed by primary sensory neurons, but little is known about the processing of the TRPM8-mediated cold information within the trigeminal sensory nuclei (TSN) and the spinal dorsal horn (DH). To address this issue, we characterized TRPM8-positive (+) neurons in the trigeminal ganglion and investigated the distribution of TRPM8+ axons and terminals, and their synaptic organization in the TSN and in the DH using light and electron microscopic immunohistochemistry in transgenic mice expressing a genetically encoded axonal tracer in TRPM8+ neurons. TRPM8 was expressed in a fraction of small myelinated primary afferent fibers (23.7%) and unmyelinated fibers (76.3%), suggesting that TRPM8-mediated cold is conveyed via C and Aδ afferents. TRPM8+ axons were observed in all TSN, but at different densities in the dorsal and ventral areas of the rostral TSN, which dominantly receive sensory afferents from intra- and peri-oral structures and from the face, respectively. While synaptic boutons arising from Aδ and non-peptidergic C afferents usually receive many axoaxonic contacts and form complex synaptic arrangements, TRPM8+ boutons arising from afferents of the same classes of fibers showed a unique synaptic connectivity; simple synapses with one or two dendrites and sparse axoaxonic contacts. These findings suggest that TRPM8-mediated cold is conveyed via a specific subset of C and Aδ afferent neurons and is processed in a unique manner and differently in the TSN and DH. |
url |
http://europepmc.org/articles/PMC3977991?pdf=render |
work_keys_str_mv |
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