European journal of pharmacology
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Activation of peripheral P2X3 and P2X2/3 receptors by endogenous ATP is essential to the development of inflammatory hyperalgesia. We have previously demonstrated that this essential role of P2X3 and P2X2/3 receptors in the development of mechanical hyperalgesia induced by the inflammatory agent carrageenan is mediated by an indirect sensitization of the primary afferent nociceptors dependent on the previous release of tumor necrosis factor alpha (TNF-α) and by a direct sensitization of the primary afferent nociceptors. Therefore, in this study we asked whether activation of P2X3 and P2X2/3 receptors contribute to the mechanical hyperalgesia induced by the inflammatory mediators involved in carrageenan-induced mechanical hyperalgesia, such as bradykinin, tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), chemokine-induced chemoattractant-1 (CINC-1), prostaglandin E₂ (PGE₂) and dopamine. ⋯ We also verified whether the activation of P2X3 and P2X2/3 receptors by endogenous ATP contributes to bradykinin-induced mechanical hyperalgesia via neutrophil migration and/or cytokine release. Co-administration of TNP-ATP or A-317491 did not affect either neutrophil migration or the increased concentration of TNF-α, IL-1β, IL-6 and CINC-1 induced by bradykinin. These findings demonstrate that the activation of P2X3 and P2X2/3 receptors by endogenous ATP mediates bradykinin-induced mechanical hyperalgesia by a mechanism that does not depend on neutrophil migration or cytokines release.
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Harmine is a beta-carboline alkaloid present in medicinal plants such as Peganum harmala that have been used as folk medicine in anticancer therapy. In this study, we demonstrated the anti-angiogenic activity of harmine using in vivo and in vitro assay systems. In vivo anti-angiogenic activity was studied using B16F-10 melanoma cells which induced capillary formation in C57BL/6 mice. ⋯ Direct treatment of the harmine also inhibited microvessel outgrowth from the rat aortic ring. Production of other factors by tumour cells which are involved in angiogenesis like cyclooxygenase (COX-2), inducible nitric oxide synthase (iNOS) and matrix metalloproteases (MMPs) were also decrease by the treatment with harmine. Our data suggest that harmine may be a strong angiogenic inhibitor with the ability to decrease the proliferation of vascular endothelial cells and to reduce expression of various pro-angiogenic factors.
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The present study was designed to investigate the ameliorative potential of spironolactone in chronic constriction injury and vincristine-induced neuropathic pain in rats. The chronic constriction injury was induced by placing four loose ligatures around the sciatic nerve, while vincristine (50 μg/kg) was administered for 10 days to induce chemotherapy-induced neuropathic pain. Acetone drop, pin-prick, hot plate and paint brush tests were performed to assess cold allodynia; mechanical and heat hyperalgesia; dynamic mechanical allodynia, respectively. ⋯ Administration of vincristine was associated with the development of allodynia and hyperalgesia without spontaneous pain, foot deformity and elevation in the levels of TNF-α. Administration of spironolactone (10 and 20 mg/kg) significantly attenuated chronic constriction injury-induced pain related behaviour and foot deformity along with attenuation of TNF-α levels, without modulating vincristine-induced neuropathic pain. The attenuating effect of spironolactone in chronic constriction injury may be due to its anti-inflammatory properties and ability to decrease pro-inflammatory cytokines, while involvement of non-inflammatory mechanisms in the pathogenesis of vincristine-induced pain may probably explain its lack of beneficial effect in chemotherapy associated pain.
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Mu-opioids (i.e. morphine, oxycodone, hydrocodone) are considered to be the primary drugs for treatment of moderate to severe acute, chronic and cancer pain. Despite their analgesic effectiveness they have several clinically significant side-effects (cognitive, motor, respiratory, cardiovascular, gastrointestinal). They also have a limited spectrum of action, being more effective for nociceptive than neuropathic pain. ⋯ It had a good separation based on dose (at least 10-fold) between side-effects (incoordination, hypolocomotion, inhibition of gastrointestinal motility) and analgesia in all models of pain tested. In addition, morphine-6-O-sulfate had a more favorable potency ratio for delay of gastrointestinal transit and analgesia when compared to morphine. These preclinical findings suggest that morphine-6-O-sulfate is a potential candidate for development as a novel opioid for management of nociceptive, neuropathic and mixed pain states.
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To investigate the in vitro effect of tanshinone IIA on leukocyte-associated hypoxia-reoxygenation injury of human brain-blood barrier (BBB), we established the BBB model by culturing purified primary human brain microvascular endothelial cells (HBMVEC) to confluence on cell culture insert. BBB was identified by tight junction, transendothelial electrical resistance (TEER) and the permeability of BBB to horseradish peroxidase (HRP). The effect of tanshinone IIA on the permeability of BBB was tested at 2 h after hypoxia and 1h after reoxygenation with or without the supernatants of activated leukocytes. ⋯ Moreover, tanshinone IIA could decrease the levels of MMP-9, TNF-α, IL-1α, IL-2, IFN-γ and reactive oxygen species in leukocytes. In conclusion, tanshinone IIA can protect BBB against leukocyte-associated hypoxia-reoxygenation injury by attenuating the activation of leukocytes and inhibiting the injury effects of leukocytic products. Tanshinone IIA may be a novel therapeutic agent for cerebral ischemia-reperfusion injury.