A dose-response study on the efficacy of tricyclic antidepressants on reducing morphine-withdrawal symptoms.

BACKGROUND: Acute detoxification may lead to withdrawal syndrome. The syndrome is sufficiently aversive in those who are morphine-dependents and thus it hinders abstinence. The opioids are most often used clinically to lighten this syndrome. Here, we evaluated the effects of tricyclic antidepressants (TCAs) in treating physical dependence to opioids upon acute detoxification in mice. MATERIALS AND METHODS: Adult NRL mice were rendered physically dependent on morphine by increasing daily doses of subcutaneous morphine for 3 days and precipitated withdrawal jumping by subcutaneous naloxone on Day 4. The mice were then assigned to receive intramuscular saline or one of the five TCAs 1 hour prior to creating naloxone-precipitated withdrawal. The withdrawal jumping frequency in 30 minutes was counted after naloxone-precipitated withdrawal. RESULTS: Our results (the newest findings) based on the equimolar dose (30 µmol/kg), showed that the severity of physical dependence on morphine could be attenuated with less intramuscular TCAs [percent maximal possible effect (MPE) < 50). Amoxapine, protriptyline, amitriptyline, clomipramine, and trimipramine produced a mean percent MPE (43, 18, 37, 45, and 36, respectively); amoxapine, protriptyline, amitriptyline, and clomipramine, also produced a dose-related effect on attenuating the severity of morphine dependence, but not trimipramine. A higher dose had a stronger effect. CONCLUSION: Amoxapine, trimipramine, protriptyline, amitriptyline, and clomipramine could have a lightening effect on physical dependence on morphine.

Protective effects of Chlorella-derived peptide on UVB-induced production of MMP-1 and degradation of procollagen genes in human skin fibroblasts.

UV exposure is known to induce premature aging, which is mediated by matrix metalloproteinase-1 (MMP-1) activity. MMP-1 mRNA expression is up-regulated by elevated cysteine-rich 61 (CYR61) and monocyte chemoattractant protein-1 (MCP-1) via action of transcription factor AP-1. Collagen is degraded by MMP-1 activity but synthesized by transforming growth factor-ß (TGF-ß) signal. Chlorella has been shown to inhibit UVB-induced MMP-1 level, however its regulatory molecular mechanisms have not been studied. In this study, Chlorella derived peptide (CDP) was added to skin fibroblasts after UVB irradiation and the expression of MMP-1, CYR61, procollagen, c-fos, c-jun, and TGF-ß receptor (TbRII) mRNA and MCP-1 production were investigated. CDP (10 or 5mg/ml) diminished UVB-induced MMP-1 and CYR61 mRNA expression and MCP-1 production, whereas, UVB-suppressed procollagen and TbRII mRNA was restored by CDP treatment. UVB-induced c-fos and c-jun expressions were also inhibited by the CDP treatment. Taken together, CDP inhibits UVB-induced MMP-1 expression in skin fibroblasts by suppressing expression of AP-1 and CYR61 and MCP-1 production.