OBJECTIVE The levels of corticosterone and noradrenalin as the two nociception modulators modify after stress condition. The propose of current study was to investigate the effect of chrysin on formalin-induced nociceptive behaviors and serum levels of corticosterone and noradrenalin in rats. MATERIALS AND METHODS Pain was induced by applying 20 μL of 5% formalin in distilled water in the sub...

Introduction: The nucleus paragigantocellularis lateralis (LPGi) is involved in the descending pain modulation. The neurostreoid, 17β-estradiol found in the PGi nucleus and modulates nociception by binding to estrogen receptors and also by allosteric interaction with NMDA receptors. In this study, the role of NMDA receptors in the 17β-estradiol-induced pain modulation was investig...

The evolutionary advantages to the suppression of pain during a stressful event (stress-induced analgesia (SIA)) are obvious, yet the reasoning behind sex-differences in the expression of this pain reduction are not. The different ways in which males and females integrate physiological stress responses and descending pain inhibition are unclear. A potential supraspinal modulator of stress-induc...

In the present study, we investigated the anti-nociceptive effect and the underlying mechanism of the analgesic-antitumor peptide (AGAP), a neurotoxin from the scorpion Buthus martensii Karsch. AGAP in doses of 0.2, 1 and 5 µg was injected intraplantarly (i.pl.) before formalin injection 10 min at the same site. The suppression by intraplantar injection of AGAP on formalin-induced spontaneous n...

BACKGROUND Numerous studies have implicated spinal extracellular signal-regulated kinases (ERKs) as mediators of nociceptive plasticity. These studies have utilized pharmacological inhibition of MEK to demonstrate a role for ERK signaling in pain, but this approach cannot distinguish between effects of ERK in neuronal and non-neuronal cells. The present studies were undertaken to test the speci...

platanus orientalis l. (platanaceae) is a medicinal tree used in iranian folklore and traditional medicine as a pain and inflammation reliever. in this study, the polyphenolic and total extract of p. orientalis leaves were prepared and their antinociceptive effects were studied in mice using the acetic acid-induced writhing, formalin and light tail flick tests. both hydroalcoholic and polypheno...

Using an animal model of colonic inflammation, the effects of intrathecal (i.t.) diazepam (0.02 mg/kg, 0.08 mg/kg and 0.15 mg/kg) on visceral pain-related behaviors and hyperalgesia associated with colonic inflammation were investigated. In this visceral pain model, acute visceral pain response was induced by intracolonic (i.c.) injection of 0.5 ml of dilute formalin (2%, 5% and 10%) in rats, a...

In this study, the effects of subcutaneous (SC) injection of pilocarpine (a cholinomimetic agent) and atropine (a muscarinic receptors antagonist) were investigated on a tonic model of orofacial pain in rats. The contribution of the endogenous analgesic opioid system was assessed using naloxone (an opioid receptors antagonist). Tonic orofacial pain was induced by SC injection of a diluted forma...

Numerous human and animal studies indirectly implicate neurons in the anterior cingulate cortex (ACC) in the encoding of the affective consequences of nociceptor stimulation. No causal evidence, however, has been put forth linking the ACC specifically to this function. Using a rodent pain assay that combines the hind-paw formalin model with the place-conditioning paradigm, we measured a learned...

Identification of the brain areas that contribute to pain is an essential undertaking towards understanding persistent pain. Areas of the basal ganglia have been proposed to play important roles in nociception as previous studies have determined the involvement of the substantia nigra pars compacta and the dorsolateral striatum in pain. The purpose of the present study was therefore to expand u...