» Articles » PMID: 24567942

Tail Flick Modification of Orexin-a Induced Changes of Electrophysiological Parameters in the Rostral Ventromedial Medulla

Overview
Journal Cell J
Specialty Cell Biology
Date 2014 Feb 26
PMID 24567942
Citations 5
Authors
Affiliations
Soon will be listed here.
Abstract

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.

Citing Articles

The ability of orexin-A to modify pain-induced cyclooxygenase-2 and brain-derived neurotrophic factor expression is associated with its ability to inhibit capsaicin-induced pulpal nociception in rats.

Shahsavari F, Abbasnejad M, Esmaeili-Mahani S, Raoof M Korean J Pain. 2022; 35(3):261-270.

PMID: 35768981 PMC: 9251390. DOI: 10.3344/kjp.2022.35.3.261.


The Lateral Hypothalamus: An Uncharted Territory for Processing Peripheral Neurogenic Inflammation.

Fakhoury M, Salman I, Najjar W, Merhej G, Lawand N Front Neurosci. 2020; 14:101.

PMID: 32116534 PMC: 7029733. DOI: 10.3389/fnins.2020.00101.


Administration of orexin receptor 1 antagonist into the rostral ventromedial medulla increased swim stress-induced antinociception in rat.

Soliemani N, Moslem A, Shamsizadeh A, Azhdari-Zarmehri H Iran J Basic Med Sci. 2016; 19(5):542-9.

PMID: 27403261 PMC: 4923475.


Orexin-a modulates firing of rat rostral ventromedial medulla neurons: an in vitro study.

Azhdari-Zarmehri H, Semnanian S, Fathollahi Y Cell J. 2015; 17(1):163-70.

PMID: 25870847 PMC: 4393666. DOI: 10.22074/cellj.2015.524.


Permanent lesion in rostral ventromedial medulla potentiates swim stress-induced analgesia in formalin test.

Shamsizadeh A, Soliemani N, Mohammad-Zadeh M, Azhdari-Zarmehri H Iran J Basic Med Sci. 2014; 17(3):209-15.

PMID: 24847424 PMC: 4016692.

References
1.
Harris G, Wimmer M, Aston-Jones G . A role for lateral hypothalamic orexin neurons in reward seeking. Nature. 2005; 437(7058):556-9. DOI: 10.1038/nature04071. View

2.
Cheng J, Chou R, Hwang L, Chiou L . Antiallodynic effects of intrathecal orexins in a rat model of postoperative pain. J Pharmacol Exp Ther. 2003; 307(3):1065-71. DOI: 10.1124/jpet.103.056663. View

3.
Heinricher M, McGaraughty S, Grandy D . Circuitry underlying antiopioid actions of orphanin FQ in the rostral ventromedial medulla. J Neurophysiol. 1998; 78(6):3351-8. DOI: 10.1152/jn.1997.78.6.3351. View

4.
Burlet S, Tyler C, Leonard C . Direct and indirect excitation of laterodorsal tegmental neurons by Hypocretin/Orexin peptides: implications for wakefulness and narcolepsy. J Neurosci. 2002; 22(7):2862-72. PMC: 6758338. DOI: 20026234. View

5.
Behbehani M, Park M, Clement M . Interactions between the lateral hypothalamus and the periaqueductal gray. J Neurosci. 1988; 8(8):2780-7. PMC: 6569401. View