Toxicity testing in the 21st century beyond environmental chemicals.

After the publication of the report titled Toxicity Testing in the 21st Century - A Vision and a Strategy, many initiatives started to foster a major paradigm shift for toxicity testing - from apical endpoints in animal-based tests to mechanistic endpoints through delineation of pathways of toxicity (PoT) in human cell based systems. The US EPA has funded an important project to develop new high throughput technologies based on human cell based in vitro technologies. These methods are currently being incorporated into the chemical risk assessment process.

Adult siRNA-induced knockdown of mGlu7 receptors reduces anxiety in the mouse.

Our knowledge regarding the molecular pathophysiology underlying anxiety disorders remains incomplete. Increasing evidence points to a role of glutamate in anxiety. The group III metabotropic glutamate receptors (mGlu4, mGlu6, mGlu7 and mGlu8 receptors) remain the least investigated glutamate receptor subtypes partially due to a delay in the development of specific pharmacological tools.

Quinazolinedione sulfonamides: a novel class of competitive AMPA receptor antagonists with oral activity.

Quinazoline-2,4-diones with a sulfonamide group attached to the N(3) ring atom constitute a novel class of competitive AMPA receptor antagonists. One of the synthesized compounds, 28, shows nanomolar receptor affinity, whereas other examples of the series display oral anticonvulsant activity in animal models.

The anticonvulsant profile of rufinamide (CGP 33101) in rodent seizure models.

Purpose: To evaluate the anticonvulsant profile and behavioral toxicity of rufinamide in animal seizure models compared to the established antiepileptic drugs (AEDs): phenytoin, phenobarbital, valproate, and ethosuximide, or vehicle.

Methods: In acute studies of anticonvulsant efficacy, the AEDs were administered via oral (CF1 mice and Sprague-Dawley rats) and intraperitoneal (CF1 mice) routes. The AEDs were assessed for their ability to inhibit seizures induced by maximal electroshock (MES) or subcutaneous pentylenetetrazol, and ability to block seizures induced by subcutaneous strychnine, bicuculline, or picrotoxin.

AMPA receptor antagonists: potential therapeutic applications.

The current review will focus on the recent patents for AMPA receptor antagonists and their claims, evidence for their therapeutic effectiveness in the treatment of epilepsy and their potential role in psychiatric and neurodegenerative disorders. It will also highlight the proposed mechanisms of action and the implications thereof for our current understanding of the biomolecular basis of these pathologies. It will conclude with a summary of what we know, but also point out the remaining uncertainties, especially as this relates to the claims in the patent under discussion.

Global down-regulation of gene expression in the brain using RNA interference, with emphasis on monoamine transporters and GPCRs: implications for target characterization in psychiatric and neurological disorders.

RNA interference (RNAi) is a natural mechanism for regulating gene expression, which exists in plants, invertebrates, and mammals. We investigated whether non-viral infusion of short interfering RNA (siRNA) by the intracerebroventricular route would enable a sequence-specific gene knockdown in the mouse brain and whether the knockdown translates into disease-relevant behavioral changes. Initially, we targeted enhanced green fluorescent protein (EGFP) in mice overexpressing EGFP.

Redistribution of GABAB(1) protein and atypical GABAB responses in GABAB(2)-deficient mice.

GABAB receptors mediate slow synaptic inhibition in the nervous system. In transfected cells, functional GABAB receptors are usually only observed after coexpression of GABAB(1) and GABAB(2) subunits, which established the concept of heteromerization for G-protein-coupled receptors. In the heteromeric receptor, GABAB(1) is responsible for binding of GABA, whereas GABAB(2) is necessary for surface trafficking and G-protein coupling.

Specific gamma-hydroxybutyrate-binding sites but loss of pharmacological effects of gamma-hydroxybutyrate in GABA(B)(1)-deficient mice.

gamma-Hydroxybutyrate (GHB), a metabolite of gamma-aminobutyric acid (GABA), is proposed to function as a neurotransmitter or neuromodulator. gamma-Hydroxybutyrate and its prodrug, gamma-butyrolactone (GBL), recently received increased public attention as they emerged as popular drugs of abuse. The actions of GHB/GBL are believed to be mediated by GABAB and/or specific GHB receptors, the latter corresponding to high-affinity [3H]GHB-binding sites coupled to G-proteins.

5-Phosphonomethylquinoxalinediones as competitive NMDA receptor antagonists with a preference for the human 1A/2A, rather than 1A/2B receptor composition.

NMDA antagonists derived from 5-phosphonomethyl-1,4-dihydroquinoxaline-2,3-dione (3a) are potent anticonvulsant agents, and display strong protective effects in the electroshock-induced convulsion assay in mice. Their preference for the human NMDAR 1A/2A over 1A/2B subunit composition was optimized, leading to (1RS,1'S)-PEAQX (9r), which shows a >100-fold selectivity.