Journal of biomedical science
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We examined scratch-inducing effects of intracisternal, intrathecal and intradermal injections of morphine and some opioid agonists in mice. Intracisternal injection of morphine (3 nmol/animal) and the mu-receptor agonist [D-Ala(2), N-Me-Phe(4), Gly(5)-ol]enkephalin (DAMGO; 0.2 nmol/animal) elicited scratching of the face, with little effect on scratching of the trunk. Intracisternal injection of the delta-receptor agonist [D-Pen(2,5)]enkephalin (DPDPE) and the kappa-receptor agonist U50488 were without effects. ⋯ Intradermal injections of morphine (3-100 nmol/site), DAMGO (1-100 nmol/site), DPDPE (10 and 100 nmol/site) and U50488 (10-100 nmol/site) did not elicit scratching of the site of injection. Intradermal injection of histamine (100 nmol/site) induced the scratching in ICR, but not ddY, mice and serotonin (30 and 50 nmol/site) elicited the scratching in either strain of mice. The results suggest that opioids induce scratching, and probably itching, through central mu-opioid receptors in the mouse.
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Endotoxin shock is characterized by systemic hypotension, hyporeactiveness to vasoconstrictors and acute lung edema. A nitric oxide synthase (NOS) inhibitor, NG-monomethyl-L-arginine (L-NMMA) has been shown to be effective in reversing acute lung injury. In the present study, we evaluated the effects of NOS blockade by different mechanisms on the endotoxin-induced changes. ⋯ Our results suggest that NO production through the iNOS pathway is responsible for endotoxin-induced lung injury. Certain cytokines such as IL-1beta are possibly involved. These changes are minimized by NOS inhibitors through different mechanisms.
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Hepatitis E is a worldwide health problem, especially in developing countries. The virus genome contains three different open reading frames (ORFs): ORF-1, which is believed to encode nonstructural proteins, and ORF-2 and ORF-3, which are believed to encode structural proteins. Presently, serologic tests for the detection of human antibodies to hepatitis E virus (HEV) infection are primarily based on the ORF-2 structural protein expressed in Escherichia coli, insect cells or synthetic peptides. ⋯ These results suggest that the recombinant ORF-2 protein is more sensitive as a diagnostic antigen for detecting antibodies to HEV in both acute-phase and convalescent-phase sera than ORF-3 protein. Copyright 1996 S. Karger AG, Basel