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Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus

Recent studies have shown a direct projection of nociceptive trigeminal afferents into the lateral parabrachial nucleus (LPBN). Information about the synaptic connectivity of these afferents may help understand how orofacial nociception is processed in the LPBN, which is known to be involved primari...

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Autores principales: An, Su Bin, Cho, Yi Sul, Park, Sook Kyung, Kim, Yun Sook, Bae, Yong Chul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10098450/
https://www.ncbi.nlm.nih.gov/pubmed/37066077
http://dx.doi.org/10.3389/fncel.2023.1162874
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author An, Su Bin
Cho, Yi Sul
Park, Sook Kyung
Kim, Yun Sook
Bae, Yong Chul
author_facet An, Su Bin
Cho, Yi Sul
Park, Sook Kyung
Kim, Yun Sook
Bae, Yong Chul
author_sort An, Su Bin
collection PubMed
description Recent studies have shown a direct projection of nociceptive trigeminal afferents into the lateral parabrachial nucleus (LPBN). Information about the synaptic connectivity of these afferents may help understand how orofacial nociception is processed in the LPBN, which is known to be involved primarily in the affective aspect of pain. To address this issue, we investigated the synapses of the transient receptor potential vanilloid 1-positive (TRPV1+) trigeminal afferent terminals in the LPBN by immunostaining and serial section electron microscopy. TRPV1 + afferents arising from the ascending trigeminal tract issued axons and terminals (boutons) in the LPBN. TRPV1+ boutons formed synapses of asymmetric type with dendritic shafts and spines. Almost all (98.3%) TRPV1+ boutons formed synapses with one (82.6%) or two postsynaptic dendrites, suggesting that, at a single bouton level, the orofacial nociceptive information is predominantly transmitted to a single postsynaptic neuron with a small degree of synaptic divergence. A small fraction (14.9%) of the TRPV1+ boutons formed synapses with dendritic spines. None of the TRPV1+ boutons were involved in axoaxonic synapses. Conversely, in the trigeminal caudal nucleus (Vc), TRPV1+ boutons often formed synapses with multiple postsynaptic dendrites and were involved in axoaxonic synapses. Number of dendritic spine and total number of postsynaptic dendrites per TRPV1+ bouton were significantly fewer in the LPBN than Vc. Thus, the synaptic connectivity of the TRPV1+ boutons in the LPBN differed significantly from that in the Vc, suggesting that the TRPV1-mediated orofacial nociception is relayed to the LPBN in a distinctively different manner than in the Vc.
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spelling pubmed-100984502023-04-14 Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus An, Su Bin Cho, Yi Sul Park, Sook Kyung Kim, Yun Sook Bae, Yong Chul Front Cell Neurosci Neuroscience Recent studies have shown a direct projection of nociceptive trigeminal afferents into the lateral parabrachial nucleus (LPBN). Information about the synaptic connectivity of these afferents may help understand how orofacial nociception is processed in the LPBN, which is known to be involved primarily in the affective aspect of pain. To address this issue, we investigated the synapses of the transient receptor potential vanilloid 1-positive (TRPV1+) trigeminal afferent terminals in the LPBN by immunostaining and serial section electron microscopy. TRPV1 + afferents arising from the ascending trigeminal tract issued axons and terminals (boutons) in the LPBN. TRPV1+ boutons formed synapses of asymmetric type with dendritic shafts and spines. Almost all (98.3%) TRPV1+ boutons formed synapses with one (82.6%) or two postsynaptic dendrites, suggesting that, at a single bouton level, the orofacial nociceptive information is predominantly transmitted to a single postsynaptic neuron with a small degree of synaptic divergence. A small fraction (14.9%) of the TRPV1+ boutons formed synapses with dendritic spines. None of the TRPV1+ boutons were involved in axoaxonic synapses. Conversely, in the trigeminal caudal nucleus (Vc), TRPV1+ boutons often formed synapses with multiple postsynaptic dendrites and were involved in axoaxonic synapses. Number of dendritic spine and total number of postsynaptic dendrites per TRPV1+ bouton were significantly fewer in the LPBN than Vc. Thus, the synaptic connectivity of the TRPV1+ boutons in the LPBN differed significantly from that in the Vc, suggesting that the TRPV1-mediated orofacial nociception is relayed to the LPBN in a distinctively different manner than in the Vc. Frontiers Media S.A. 2023-03-30 /pmc/articles/PMC10098450/ /pubmed/37066077 http://dx.doi.org/10.3389/fncel.2023.1162874 Text en Copyright © 2023 An, Cho, Park, Kim and Bae. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
An, Su Bin
Cho, Yi Sul
Park, Sook Kyung
Kim, Yun Sook
Bae, Yong Chul
Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus
title Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus
title_full Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus
title_fullStr Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus
title_full_unstemmed Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus
title_short Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus
title_sort synaptic connectivity of the trpv1-positive trigeminal afferents in the rat lateral parabrachial nucleus
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10098450/
https://www.ncbi.nlm.nih.gov/pubmed/37066077
http://dx.doi.org/10.3389/fncel.2023.1162874
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