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 investigated by assess...

in the present study, the effects of intracerebroventricular (icv) administration of normal saline (control), histamine, mepyramine (a histamine h1-receptor antagonist) and ranitidine (a histamine h2-receptor antagonist) were investigated on the formalin-induced pain in rabbits. subcutaneous (sc) injection of a formalin (100 μl, 5%) solution into the ventral surface of the right hind paw was pe...

Introduction: The concentration of noradrenalin and corticosterone as the two nociception modulators change after fasting or stress situation. The aim of present study was to investigate the effect of food deprivation on formalin-induced nociceptive behaviours and plasma levels of noradrenalin and corticosterone in rats. Methods: Food was withdrawn 12, 24 and 48 h prior to performing the formal...

Previous studies have shown that paragigantocellularis nucleus (PGI) neurons contain some neurotransmitters such as GABA, neuropeptides, monoamines, substance P, enkephalin and serotonin. It has been suggested that PGI is a main cholinergic source in the rat’s brain stem. There are few evidences on the presence and importance of cholinergic receptors on PGI neurons with regard to nociception. I...

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 ...

background and objectives: previous studies have shown the antinociceptive effect of morphine in animal models, but the specific anti-pain consequence of the abuse drug in female animals is unclear. the present research showed the morphine antinociception in female wistar rats using formalin test. materials and methods: subjects were 40 female wistar rats purchased from pasteur institute of ira...