65 The decreased sensitivity to clonidine would appear to be an important and reversible sign of withdrawal in the guinea-pig ileum. Such interactions between opiate receptors and a-adren-ergic receptors do not appear to occur in the mouse vas deferens (Gillan et al., 1979). However, vasa deferentia from rats treated chronically with clonidine showed lower sensitivity to the inhibitory effects ...

Morphine is a well-known mu-opioid receptor (MOR) agonist and an efficient analgesic, but its long-term use inevitably leads to drug addiction and tolerance. Here, we show that specific inhibition of beta-arrestin2 with its siRNA lentivirus microinjected in mice periaqueductal gray matter (PAG) significantly improved both acute and chronic morphine analgesia and delayed the tolerance in the hot...

Opioid agonists are the most effective treatment for pain, but their use is limited by side effects, tolerance and fears of addiction and dependence. A major goal of opioid research is to develop agonists that have high analgesic efficacy and a low profile for side effects, tolerance, addiction and dependence. Unfortunately, there is a serious lack of experimental data comparing the degree to w...

AIM ETA receptor antagonists reverse opioid tolerance but the involvement of ETB receptors is unknown. In morphine or oxycodone tolerant mice we investigated (1) the effect of ETB receptor agonist, IRL-1620, on analgesic tolerance; (2) changes in expression of the brain ETA and ETB receptors; and (3) alterations in the brain VEGF, NGF, PI3K and notch-1 expression. MAIN METHODS Body weight, bo...

BACKGROUND Previous studies have suggested that melatonin may produce antinociception through peripheral and central mechanisms. Based on the preliminary encouraging results of studies of the effects of melatonin on pain modulation, the important question has been raised of whether there is a dose relationship in humans of melatonin on pain modulation. OBJECTIVE The objective was to evaluate ...

Tissue injury is known to produce inflammation and pain. Synaptic potentiation between peripheral nociceptors and spinal lamina I neurons has been proposed to serve as a trigger for chronic inflammatory pain. Gastrodin is a main bioactive constituent of the traditional Chinese herbal medicine Gastrodia elata Blume, which has been widely used as an analgesic since ancient times. However, its und...

Lichens produce a great variety of secondary metabolites and most of them are unique. These chemically diverse lichen substances accumulate on the outer surfaces of the hyphae. They have several biological activities, including photoprotection against intense radiation, as well as allelochemical, antiviral, antitumor, antibacterial, antiherbivore, antioxidant, antipyretic, and analgesic action....

Fentanyl is considered to be an effective, transdermal treatment of chronic, cancer, and noncancer pain. This noninterventional, clinical practice-based study, on 426 patients attending 42 practices, assessed a proprietary, Aloe vera-containing, transdermal fentanyl matrix patch (Fentavera), for its analgesic effects, patients' quality of life (QoL) effects, tolerability, and adhesiveness. Stud...