Characterization of the interaction between fenamates and hippocampal neuron GABA(A) receptors.
(1/11)
Fenamate NSAIDs have several central effects, including anti-epileptic and neuroprotective actions. The underlying mechanism(s) of these actions are not presently understood. In this study, the effects of five members of the fenamate NSAID group were investigated on native ligand-gated ion channels expressed in cultured rat hippocampal neurons. All fenamates tested (1-100 microM) dose-dependently potentiated GABA-evoked currents; mefenamic acid (MFA) was the most potent and efficacious and was found to shift the GABA dose-response curve to the left without effect on the maximum amplitude or the GABA Hill Slope. The modulation of GABA receptors by MFA was not reduced in the presence of the benzodiazepine antagonist, flumazenil (10 microM) and was moderately voltage-dependent. MFA at concentrations >or=10 microM evoked dose-dependent currents in the absence of GABA. These currents were potentiated by diazepam (1 microM) and blocked by bicuculline (10 microM). The MFA (50 microM) current-voltage relationship and reversal potential were similar to that evoked by GABA. MFA (1-100 microM) had no effects on sub-maximal glycine, glutamate or NMDA evoked currents. These data show that fenamate NSAIDs are a highly effective class of GABA(A) receptor modulator and activators. (+info)
Competitive inhibition of organic anion transporting polypeptide 1c1-mediated thyroxine transport by the fenamate class of nonsteroidal antiinflammatory drugs.
(2/11)
Selective inhibition of the tumor marker AKR1B10 by antiinflammatory N-phenylanthranilic acids and glycyrrhetic acid.
(5/11)
A human aldose reductase-like protein, AKR1B10 in the aldo-keto reductase (AKR) superfamily, was recently identified as a tumor marker of several types of cancer. Tolrestat, an aldose reductase inhibitor (ARI), is known to be the most potent inhibitor of the enzyme. In this study, we compared the inhibitory effects of other ARIs including flavonoids on AKR1B10 and aldose reductase to evaluate their specificity. However, ARIs showed lower inhibitory potency for AKR1B10 than for aldose reductase. In the search for potent and selective inhibitors of AKR1B10 from other drugs used clinically, we found that non-steroidal antiinflammatory N-phenylanthranilic acids, diclofenac and glycyrrhetic acid competitively inhibited AKR1B10, showing K(i) values of 0.35-2.9 microM and high selectivity to this enzyme (43-57 fold versus aldose reductase). Molecular docking studies of mefenamic acid and glycyrrhetic acid in the AKR1B10-nicotinamide adenine dinucleotide phosphate (NADP(+)) complex and site-directed mutagenesis of the putative binding residues suggest that the side chain of Val301 and a hydrogen-bonding network among residues Val301, Gln114 and Ser304 are important for determining the inhibitory potency and selectivity of the non-steroidal antiinflammatory drugs. Thus, the potent and selective inhibition may be related to the cancer chemopreventive roles of the drugs, and their structural features may facilitate the design of new anti-cancer agents targeting AKR1B10. (+info)
Trapping of palindromic ligands within native transthyretin prevents amyloid formation.
(6/11)