Formalin as a chemical noxious stimulus evokes a biphasic pain that its second phase as a chronic inflammatory pain is similar to clinical pain. In this study, we used 40 NMRI male rats (250-300 g), and experiments were carried out considering ethical rules. Experiments were performed in normal and morphine addicted rats, the addiction was induced by Leung method. Behaviors of flinching and lic...

Lipocalin-2 (LCN2) is an acute-phase protein induced by injury, infection, or other inflammatory stimuli. LCN2 binds small hydrophobic ligands and interacts with cell surface receptor to regulate diverse cellular processes. The role of LCN2 as a chemokine inducer in the central nervous system (CNS) has been previously reported. Based on the previous participation of LCN2 in neuroinflammation, w...

ABSTRACTPrevious studies have shown the role of opioid receptors located in the nucleus cuneiformis (CnF) in acute pain, but not in chronic pain models. In the present study, we have determined that possible effects of these receptors at the CnF on both early and late phases of formalin test following local and systemic morphine administration. Each rat was given a subcutaneous 50-μl injection ...

Introduction: Some evidence demonstrates endogenous inhibitory pathways of pain involved in the interphase (phase between early and later phase) of the formalin test. We previously showed that swimming stress modulates the pain-related behaviors during the interphase of the formalin test. In this study, we evaluated the role of the endogenous opioid system in modulating nociceptive responses of...

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 pai...

BACKGROUND Affections are thought to regulate pain perception through the descending pain inhibitory system in the central nervous system. In this study, we examined in mice the affective change by inhalation of the lemon oil, which is well used for aromatherapy, and the effect of lemon odor on pain sensation. We also examined the anterior cingulate cortex (ACC) and descending pain inhibitory s...

Introduction: Previously, we demonstrated that i.p. injection of aqueous extract prepared from aerial parts of Drosera Spatulata (Droseraceae) can induced remarkable analgesia in both phases of formalin test in rats. Because, analgesia induced in acute phase of formalin test mainly mediated by activation of central analgesic mechanisms and also paragigantocellularis (PGi) nucleus is part of bra...

Ellagic acid is a healthy food and drug developed by foreign countries. It has been proven that it is not only anti-cancerous and anti-mutational, but also anti-microbial and antiviral. In this study, we examined the effect of ellagic acid alleviates inflammatory pain and paclitaxel-induced neuropathic pain in murine models. It was shown that the effect of ellagic acid could alleviate acetic ac...

introduction: glabrous skin and hairy skin are innervated by different types of noxious fibers. however, the different nociceptive behaviors induced by formalin, a commonly used model of acute inflammatory pain, have not yet been systematically examined in the glabrous and hairy skin. methods: in this study, we compared nociceptive behaviors induced by formalin injections (2%, 4%, and 8%) into ...