The Experts below are selected from a list of 14517 Experts worldwide ranked by ideXlab platform

Scott B Meikrantz - One of the best experts on this subject based on the ideXlab platform.

Tomoki Nishiyama - One of the best experts on this subject based on the ideXlab platform.

  • interaction between a NMDA Receptor Antagonist ap 5 and an ampa Receptor Antagonist ym 872 in antinociception in the spinal cord
    Acta Anaesthesiologica Scandinavica, 2008
    Co-Authors: Tomoki Nishiyama
    Abstract:

    BACKGROUND: The intrathecal N-methyl-D-aspartate (NMDA) Receptor Antagonist, AP-5 and the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) Receptor Antagonist, YM 872 showed inhibition on both acute and facilitated nociception in our previous study. The present study was performed to investigate the interaction between intrathecal AP-5 and YM 872 in antinociception for acute and chronic nociception. METHODS: Sprague-Dawley rats with lumbar intrathecal catheters were tested for their thermal tail withdrawal response and for their paw flinches by formalin injection after intrathecal administration of AP-5 or YM 872. The effects of the combination were tested by an isobolographic analysis using 50% effective dose (ED50). Total fractional dose was calculated as (ED50 dose of AP-5 in combination)/(ED50 dose of AP-5 alone)+(ED50 dose of YM 872 in combination)/(ED50 dose of YM 872 alone). RESULTS: Intrathecally administered AP-5, YM 872, and their combination produced dose-dependent increases of the tail-flick latency and decreases in the number of flinches in both phase 1 and 2 of the formalin test. The ED50 values of the combination were significantly lower than the calculated additive values (P<0.01). Total fractional dose value was 0.22 in the tail flick test, 0.12 in the phase 1 and 0.14 in the phase 2 of the formalin test. CONCLUSION: An NMDA Receptor Antagonist, AP-5 and an AMPA Receptor Antagonist, YM 872 had synergistic antinociceptive effects on both acute thermal and inflammatory induced acute and facilitated nociception.

  • this article has been retracted interaction between a NMDA Receptor Antagonist ap 5 and an ampa Receptor Antagonist ym 872 in antinociception in the spinal cord
    Acta Anaesthesiologica Scandinavica, 2008
    Co-Authors: Tomoki Nishiyama
    Abstract:

    Background: The intrathecal N-methyl-d-aspartate (NMDA) Receptor Antagonist, AP-5 and the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) Receptor Antagonist, YM 872 showed inhibition on both acute and facilitated nociception in our previous study. The present study was performed to investigate the interaction between intrathecal AP-5 and YM 872 in antinociception for acute and chronic nociception. Methods: Sprague–Dawley rats with lumbar intrathecal catheters were tested for their thermal tail withdrawal response and for their paw flinches by formalin injection after intrathecal administration of AP-5 or YM 872. The effects of the combination were tested by an isobolographic analysis using 50% effective dose (ED50). Total fractional dose was calculated as (ED50 dose of AP-5 in combination)/(ED50 dose of AP-5 alone)+(ED50 dose of YM 872 in combination)/(ED50 dose of YM 872 alone). Results: Intrathecally administered AP-5, YM 872, and their combination produced dose-dependent increases of the tail-flick latency and decreases in the number of flinches in both phase 1 and 2 of the formalin test. The ED50 values of the combination were significantly lower than the calculated additive values (P<0.01). Total fractional dose value was 0.22 in the tail flick test, 0.12 in the phase 1 and 0.14 in the phase 2 of the formalin test. Conclusion: An NMDA Receptor Antagonist, AP-5 and an AMPA Receptor Antagonist, YM 872 had synergistic antinociceptive effects on both acute thermal and inflammatory induced acute and facilitated nociception.

Bruce Baron - One of the best experts on this subject based on the ideXlab platform.

Daniel T Monaghan - One of the best experts on this subject based on the ideXlab platform.

  • structure activity analysis of a novel nr2c nr2d preferring NMDA Receptor Antagonist 1 phenanthrene 2 carbonyl piperazine 2 3 dicarboxylic acid
    British Journal of Pharmacology, 2004
    Co-Authors: Bihua Feng, Heong Wai Tse, Donald A Skifter, Richard M Morley, David E Jane, Daniel T Monaghan
    Abstract:

    (2S*,3R*)-1-(biphenyl-4-carbonyl)piperazine-2,3-dicarboxylic acid (PBPD) is a moderate affinity, competitive N-methyl-d-aspartate (NMDA) Receptor Antagonist with an atypical pattern of selectivity among NMDA Receptor 2 subunit (NR2) subunits. We now describe the activity of several derivatives of PBPD tested at both rat brain NMDA Receptors using l-[3H]-glutamate binding assays and at recombinant Receptors expressed in Xenopus oocytes. Substituting various branched ring structures for the biphenyl group of PBPD reduced NMDA Receptor activity. However, substituting linearly arranged ring structures - fluorenone or phenanthrene groups - retained or enhanced activity. Relative to PBPD, the phenanthrene derivative (2S*, 3R*)-1-(phenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid (PPDA) displayed a 30- to 78-fold increase in affinity for native NMDA Receptors. At recombinant Receptors, PPDA displayed a 16-fold (NR2B) to 94-fold (NR2C) increase in affinity over PBPD. Replacement of the biphenyl group of PBPD with a 9-oxofluorene ring system resulted in small changes in Receptor affinity and subtype selectivity. 2'-Bromo substitution on the biphenyl group of PBPD reduced Antagonist affinity 3- to 5-fold at NR2A-, NR2B- and NR2D-containing Receptors, but had little effect on NR2C-containing Receptors. In contrast, 4'-fluoro substitution of the biphenyl ring of PBPD selectively increased NR2A affinity. The aromatic rings of PBPD and PPDA increase Antagonist affinity and appear to interact with a region of the NMDA Receptor displaying subunit heterogeneity. PPDA is the most potent and selective NR2C/NR2D-preferring Antagonist yet reported and thus may be useful in defining NR2C/NR2D function and developing related Antagonists with improved NMDA Receptor subtype selectivity. British Journal of Pharmacology (2004) 141, 508-516. doi:10.1038/sj.bjp.0705644

Timothy C Mccloskey - One of the best experts on this subject based on the ideXlab platform.