UNLABELLED Morphine, an opioid analgesic commonly prescribed and abused, produces immune-altering effects. Whether morphine's antinociceptive and immunologic effects occur concurrently is unknown. Therefore, we investigated the time course of morphine's immunologic and antinociceptive effects. Rats were given a 15-mg/kg morphine injection (subcutaneously), and experimental assessments were take...

Gossypin is a bioflavonoid isolated from Hibiscus Vitifolus Linn. The antinociception activity of gossypin has been studied in comparison with the standard antinociception agent, morphine, against the experimental model of tonic continuous pain produced by formalin. Formalin (0.1ml of 1% solution) was injected under the plantar surface of right hind paw of mice and the time an animal spent in l...

The rostral ventromedial medulla (RVM) modulates nociception through changes in the activity of two classes of neuron, ON- and OFF-cells. The activity of these neurons is regulated, in part, by input from the periaqueductal gray (PAG). The objective of this study was to determine whether PAG-mediated antinociception is associated with excitation of both ON- and OFF-cells in the RVM. Microinject...

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...

We evaluated the modulation by Na+,K+-ATPase inhibitors of morphine-induced antinociception in the tail-flick test and [3H]naloxone binding to forebrain membranes. The antinociception induced by morphine (1-32 mg/kg, s.c.) in mice was dose-dependently antagonized by ouabain (1-10 ng/mouse, i.c.v.), which produced a significant shift to the right of the morphine dose-response curve. The i.c.v. a...

  In this study, the effects of lead acetate on two types of pain (nociception and inflammation) induced by formalin and its interaction with the opioid system and morphine-induced analgesia were examined. Male albino mice weighing 22-27 g were used in the experiments. Morphine was administered subcutaneously 30 minutes before formalin injection. Lead acetate was intraperitoneally administered ...

BACKGROUND AND PURPOSE For patients experiencing inadequate analgesia and intolerable opioid-related side effects on one strong opioid analgesic, pain relief with acceptable tolerability is often achieved by rotation to a second strong opioid. These observations suggest subtle pharmacodynamic differences between opioids in vivo. This study in rats was designed to assess differences between opio...

The antinociception induced by the intrathecal coadministration of combinations of morphine with the nonsteroidal anti-inflammatory drugs (NSAIDs) naproxen, piroxicam, metamizol, diclofenac and ketoprofen was studied by isobolographic analysis in the acetic acid writhing test of mice. The effective dose that produced 50% antinociception (ED(50)) was calculated from the log dose-response curve o...