Cargando…
Tail Flick Modification of Orexin-A Induced Changes of Electrophysiological Parameters in The Rostral Ventromedial Medulla
OBJECTIVE: It is well known that intracerebroventricular (ICV) and supraspinal injections of orexin-A elicit analgesia, but the mechanism(s) of action remains unidentified. This study aims to characterize the effect of orexin-A on rostral ventromedial medulla (RVM) neurons which are involved in the...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royan Institute
2014
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072083/ https://www.ncbi.nlm.nih.gov/pubmed/24567942 |
_version_ | 1782322900478459904 |
---|---|
author | Azhdari-Zarmehri, Hassan Semnanian, Saeed Fathollahi, Yaghoub Pakdel, Firouz Ghaderi |
author_facet | Azhdari-Zarmehri, Hassan Semnanian, Saeed Fathollahi, Yaghoub Pakdel, Firouz Ghaderi |
author_sort | Azhdari-Zarmehri, Hassan |
collection | PubMed |
description | OBJECTIVE: It is well known that intracerebroventricular (ICV) and supraspinal injections of orexin-A elicit analgesia, but the mechanism(s) of action remains unidentified. This study aims to characterize the effect of orexin-A on rostral ventromedial medulla (RVM) neurons which are involved in the descending nociception modulating pathway. MATERIALS AND METHODS: In this experimental study, we injected orexin-A or vehicle di- rectly into rats’ ICV while the tail flick (TF) latencies were measured and the on- and off-cell firing activities were monitored for more than 60 minutes. RESULTS: In response to noxious stimuli on the tail, we observed increased firing rate of on-cells and a decreased association with the firing rate of off-cells and in neutral cells the firing rate was unchanged just prior to tail flicking. ICV injection of orexin-A decreased the spontaneous firing rate of on-cells (the type of RVM neurons believed to have facilitatory action on nociception). Furthermore, orexin-A increased firing rate of off-cells (the type of RVM neurons believed to have an inhibitory action on nocicep- tion). Orexin-A reduced the TF-related responses of on-cells and TF-related pause duration of off-cells. CONCLUSION: These results have shown that the analgesic effect produced by orexin-A may be induced by brainstem neurons. It is suggested that the orexinergic system from the hypothalamus to the RVM may have a potential role in modulation of nociceptive transmission. |
format | Online Article Text |
id | pubmed-4072083 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Royan Institute |
record_format | MEDLINE/PubMed |
spelling | pubmed-40720832014-07-09 Tail Flick Modification of Orexin-A Induced Changes of Electrophysiological Parameters in The Rostral Ventromedial Medulla Azhdari-Zarmehri, Hassan Semnanian, Saeed Fathollahi, Yaghoub Pakdel, Firouz Ghaderi Cell J Original Article OBJECTIVE: It is well known that intracerebroventricular (ICV) and supraspinal injections of orexin-A elicit analgesia, but the mechanism(s) of action remains unidentified. This study aims to characterize the effect of orexin-A on rostral ventromedial medulla (RVM) neurons which are involved in the descending nociception modulating pathway. MATERIALS AND METHODS: In this experimental study, we injected orexin-A or vehicle di- rectly into rats’ ICV while the tail flick (TF) latencies were measured and the on- and off-cell firing activities were monitored for more than 60 minutes. RESULTS: In response to noxious stimuli on the tail, we observed increased firing rate of on-cells and a decreased association with the firing rate of off-cells and in neutral cells the firing rate was unchanged just prior to tail flicking. ICV injection of orexin-A decreased the spontaneous firing rate of on-cells (the type of RVM neurons believed to have facilitatory action on nociception). Furthermore, orexin-A increased firing rate of off-cells (the type of RVM neurons believed to have an inhibitory action on nocicep- tion). Orexin-A reduced the TF-related responses of on-cells and TF-related pause duration of off-cells. CONCLUSION: These results have shown that the analgesic effect produced by orexin-A may be induced by brainstem neurons. It is suggested that the orexinergic system from the hypothalamus to the RVM may have a potential role in modulation of nociceptive transmission. Royan Institute 2014 2014-05-25 /pmc/articles/PMC4072083/ /pubmed/24567942 Text en Any use, distribution, reproduction or abstract of this publication in any medium, with the exception of commercial purposes, is permitted provided the original work is properly cited http://creativecommons.org/licenses/by/2.5/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Article Azhdari-Zarmehri, Hassan Semnanian, Saeed Fathollahi, Yaghoub Pakdel, Firouz Ghaderi Tail Flick Modification of Orexin-A Induced Changes of Electrophysiological Parameters in The Rostral Ventromedial Medulla |
title | Tail Flick Modification of Orexin-A Induced Changes
of Electrophysiological Parameters in The Rostral
Ventromedial Medulla |
title_full | Tail Flick Modification of Orexin-A Induced Changes
of Electrophysiological Parameters in The Rostral
Ventromedial Medulla |
title_fullStr | Tail Flick Modification of Orexin-A Induced Changes
of Electrophysiological Parameters in The Rostral
Ventromedial Medulla |
title_full_unstemmed | Tail Flick Modification of Orexin-A Induced Changes
of Electrophysiological Parameters in The Rostral
Ventromedial Medulla |
title_short | Tail Flick Modification of Orexin-A Induced Changes
of Electrophysiological Parameters in The Rostral
Ventromedial Medulla |
title_sort | tail flick modification of orexin-a induced changes
of electrophysiological parameters in the rostral
ventromedial medulla |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072083/ https://www.ncbi.nlm.nih.gov/pubmed/24567942 |
work_keys_str_mv | AT azhdarizarmehrihassan tailflickmodificationoforexinainducedchangesofelectrophysiologicalparametersintherostralventromedialmedulla AT semnaniansaeed tailflickmodificationoforexinainducedchangesofelectrophysiologicalparametersintherostralventromedialmedulla AT fathollahiyaghoub tailflickmodificationoforexinainducedchangesofelectrophysiologicalparametersintherostralventromedialmedulla AT pakdelfirouzghaderi tailflickmodificationoforexinainducedchangesofelectrophysiologicalparametersintherostralventromedialmedulla |