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...

D-amino acid oxidase (DAO) is an enzyme catalyzing oxidative deamination of neutral and polar d-amino acids and is expressed in the kidneys, liver, and central nervous system (CNS) including the spinal cord. We have previously demonstrated that DAO gene deletion/mutation by using mutant ddY/DAO(-/-) mice and systemic administration of the DAO inhibitor sodium benzoate blocked formalin-induced h...

  In the present study, the effect of contralateral and bilateral electrolytic lesions of the nucleus reticularis paragigantocellularis (PGi) on tonic pain was assessed in rats. Pain-related behavior was evaluated using the formalin test 7 days after the lesion was made. PGi lesions did not produce any marked changes in the early phase of the formalin test, but significantly increased pain sens...

This study investigated whether immediate acupuncture effects in the acupoint are histamine dependent. Both histamine injection and manual acupuncture stimulation increased the pain threshold (PT) after treatment compared with the model group (P < 0.01), producing an analgesic effect. After pretreatment with clemastine, an H1 receptor antagonist and an antipruritic, the increase in the animals'...

Objective(s): Intracerebroventricular injection of orexin-A (hypocretin-1) antagonist has been shown to inhibit stress-induced analgesia. However the locations of central sites that may mediate these effects have not been totally demonstrated. This study was performed to investigate the role of rostral ventromedial medulla (RVM) orexin receptor 1 in stress-induced analgesia (SIA). Materials and...

Introduction: Uncoupling protein 2 (UCP2) in the inner mitochondrial membrane changes the activity of KATP channels and the cell excitability, probably by decreasing the ATP production. Given the expression of UCP2 in primary afferent neurons, and the importance of these channels in morphine-induced analgesia, genipin, an UCP2 inhibitor, may affect these processes, when administrated intrath...