The µ-opioid receptor gene polymorphism 118A>G weakens the pharmacological action of buprenorphine.

AIMS: Opioids are commonly used analgesics for moderate to severe pain, but levels of drug effect vary among individuals. As for the mechanisms underlying these individual differences, there have been reports suggesting effects of polymorphisms in the gene encoding µ-opioid receptor (OPRM1). However, whether these polymorphisms affect the actions of µ-opioid receptor partial agonists has yet to be determined. This study aimed to assess differences in the pharmacological actions of buprenorphine, a µ-opioid receptor partial agonist, due to a polymorphism (A118G, rs1799971) in the OPRM1 gene in humans. MATERIALS AND METHODS: Ten healthy adult men (5 with OPRM1 c.118AA and 5 with OPRM1 c.118GG) received a single intravenous dose of buprenorphine hydrochloride at 0.001 mg/kg. Blood samples were collected up to 360 minutes after drug administration to assess the pharmacokinetics of buprenorphine. Nociceptive thresholds (temperature), digital symbol substitution test (DSST), and visual analog self-rating scale (VAS) for subjective symptoms were also evaluated over time to assess the pharmacodynamics. RESULTS: Nociceptive thresholds were significantly increased in the AA as compared to the GG group after buprenorphine administration (p = 0.025), while the DSST scores were significantly lower in the AA group (p < 0.001). The VAS scores for drowsiness (p < 0.001), malaise (p < 0.001), nausea (p < 0.001), and euphoria (p = 0.004) were higher in the AA than in the GG group. CONCLUSION: Levels of pharmacological actions of a µ-opioid receptor partial agonist vary in accordance with a polymorphism in the OPRM1 gene (A118G).

Mild electrical stimulation with heat shock reduces inflammatory symptoms in the imiquimod-induced psoriasis mouse model.

Psoriasis is a chronic skin disease caused by immune disorder. The chronic skin inflammation involves inflammatory molecules that are released from T lymphocytes and keratinocytes. Therefore, developing an anti-inflammatory therapy that is suitable for long-term treatment is needed. Electrical stimulation induces biological responses by modulating intracellular signaling pathways. Our previous studies showed that the optimized combination treatment of mild electrical stimulation (MES, 0.1-millisecond; ms, 55-pulses per second; pps) and heat shock (HS, 42°C) modulates inflammatory symptoms of metabolic disorders and chronic kidney disease in mice models and clinical trials. Here, we investigated the effect of MES+HS treatment on imiquimod-induced psoriasis mouse model. Topical application of imiquimod cream (15 mg) to mice ear induced keratinocyte hyperproliferation and psoriasis-like inflammation. In MES+HS-treated mice, imiquimod-induced skin hyperplasia was significantly decreased. MES+HS treatment reduced the protein expression of IL-17A and the infiltration of CD3-positive cells in lesioned skin. In addition, MES+HS-treated mice had decreased mRNA expression level of antimicrobial molecules (S100A8 and Reg3γ) which aggravate psoriasis. In IL-17A-stimulated HaCaT cells, MES+HS treatment significantly lowered the mRNA expression of aggravation markers (S100A8, S100A9 and ß-defensin2). Taken together, our study suggested that MES+HS treatment improves the pathology of psoriasis via decreasing the expression of inflammatory molecules.

Effects of dosing interval on the pharmacokinetic and pharmacodynamic interactions between the oral adsorbent AST-120 and triazolam in humans.

OBJECTIVE: The objective of this study was to evaluate the pharmacokinetic and pharmacodynamic interactions between the oral adsorbent AST-120 and triazolam. METHODS: In this randomized, cross-over study, 12 healthy volunteers received a single oral dose of triazolam 0.25 mg alone or with AST-120 2 g given 0, 30 or 60 min before triazolam administration. RESULTS: The area under the plasma triazolam concentration-time curve (AUC(0-∞)) significantly decreased with simultaneous AST-120 + triazolam (alone vs simultaneous: 10.9 ± 6.0 vs 6.4 ± 2.6 ng·h/mL, p = 0.003). Triazolam-induced impairment in psychomotor performance assessed by the digit symbol substitution test was significantly attenuated when AST-120 was administered simultaneously. No significant changes in pharmacokinetic and pharmacodynamic parameters were observed when AST-120 was given 30 or 60 min before triazolam administration. CONCLUSIONS: Administering AST-120 simultaneously with triazolam affects the pharmacokinetics and pharmacodynamics of triazolam. Dosing AST-120 at least 30 min before triazolam administration may avoid these interactions.