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

Shamsizadeh, Ali and Soliemani, Neda and Mohammad-Zadeh, Mohammad and Azhdari-, Hassan (2014) Permanent lesion in rostral ventromedial medulla potentiates swim stress-induced analgesia in formalin test. Iranian Journal of Basic Medical Sciences, 17 (3). pp. 209-215.

[img]
Preview
Text
IJBMS_Volume 17_Issue 3_Pages 209-215.pdf

Download (752kB) | Preview
Official URL: http://ijbms.mums.ac.ir/article_2408.html

Abstract

Objective(s): There are many reports about the role of rostral ventromedial medulla (RVM) in modulating stress-induced analgesia (SIA). In the previous study we demonstrated that temporal inactivation of RVM by lidocaine potentiated stress-induced analgesia. In this study, we investigated the effect of permanent lesion of the RVM on SIA by using formalin test as a model of acute inflammatory pain. Materials and Methods: Three sets of experiments were conducted: (1) Application of stress protocol (2) Formalin injection after exposing the animals to the swim stress (3) Either the relevant vehicle or dopamine receptor 1 (D1) agonist R-SKF38393 was injected into the RVM to cause a lesion. For permanent lesion of RVM, R-SKF38393 was injected into the RVM. Forced swim stress in water was employed in adult male rats. Nociceptive responses were measured by formalin test (50µl injection of formalin 2 subcutaneously into hind paw) and pain related behaviors were monitored for 90 min. Results: In the unstressed rats, permanent lesion of the RVM by R-SKF38393 decreased formalin-induced nociceptive behaviors in phase 1, while in stressed rats, injection of R-SKF38393 into the RVM potentiated swim stress-induced antinociception in phase 1 and interphase, phase 2A of formalin test. Furthermore, R-SKF38393 had pronociceptive effects in phase2B whereas injections of R-SKF38393 resulted in significant difference in nociceptive bahaviours in all phases of formalin test (P<0.05). Conclusion: The result of the present study demonstrated that permanent inactivation of RVM can potentiate stress-induced analgesia in formalin test.

Item Type: Article
Subjects: QT physiology
Divisions: Journals > Iranian J Basic Medical Sciences
Depositing User: ijbms ijbms
Date Deposited: 08 Oct 2017 15:38
Last Modified: 08 Oct 2017 15:38
URI: http://eprints.mums.ac.ir/id/eprint/7965

Actions (login required)

View Item View Item