Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.14.99.3 (heme oxygenase)
 4,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Controversies surround the possible long-term physiological and psychological consequences of opioid use. Analgesic tolerance and addiction are commonly at the center of these controversies, but other concerns exist as well. A growing body of evidence suggests that hyperalgesia caused by the chronic administration of opioids can occur in laboratory animals and in humans. In these studies we describe a murine model of opioid-induced hyperalgesia (OIH). After the treatment of mice for 6 days with implanted morphine pellets followed by their removal, both thermal hyperalgesia and mechanical allodynia were documented. Additional experiments demonstrated that prior morphine treatment also increased formalin-induced licking behavior. These effects were intensified by intermittent abstinence accomplished through administration of naloxone during morphine treatment. Experiments designed to determine if the mu-opioid receptor mediated OLH in our model revealed that the relatively-selective mu-opioid receptor agonist fentanyl induced the thermal hyperalgesia and mechanical allodynia characteristic of OIH when administered in intermittent boluses over 6 days. In complimentary experiments we found that CXBK mice which have reduced mu-opioid receptor binding displayed no significant OIH after morphine treatment. Finally, we explored the pharmacological sensitivities of OIH. We found that the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801, the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) and the heme oxygenase (HO) inhibitor tin protoporphyrin (Sn-P) dose-dependently reduced OIH in this model while the NSAID indomethacin had no effect. Thus we have characterized a murine model of OIH which will be useful in the pursuit of the molecular mechanisms underlying this phenomenon.
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PMID:A murine model of opioid-induced hyperalgesia. 1116 71

Opiate addiction has been reported to contribute to the progression of renal injury. In addition, opiate addiction is a major risk factor for the development of human immunodeficiency virus-associated nephropathy. In the present study, we evaluated the effects of morphine, an active metabolite of heroin, on glomerular epithelial cell (GEC) growth and the involved molecular mechanism. At lower concentrations, morphine promoted GEC proliferation; however, at higher concentrations, morphine triggered apoptosis. Antioxidants inhibited morphine-induced proliferation as well as apoptosis. Similarly, free radical scavengers prevented morphine-induced GEC proliferation and apoptosis. Because proliferative and proapoptotic effects of morphine were inhibited by free radical scavengers as well as antioxidants, it appears that these effects of morphine are mediated through oxidative stress. Hemin, an inducer of heme oxygenase (HO) activity, inhibited GEC proliferation and promoted GEC apoptosis under basal and morphine-stimulated conditions. On the other hand, zinc protoporphyrin, an inhibitor of HO activity, promoted GEC proliferation and inhibited GEC apoptosis under basal as well as morphine-stimulated conditions. These findings suggest that HO activity is directly related to GEC apoptosis and inversely related to GEC proliferation. Morphine, de novo, had bimodal effects on HO activity: lower concentrations increased and higher concentrations decreased HO activity. It appears that HO activity may be modifying morphine-induced GEC growth.
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PMID:Role of oxidative stress and heme oxygenase activity in morphine-induced glomerular epithelial cell growth. 1281 15