Pharmacological characterisation of S 47445, a novel positive allosteric modulator of AMPA receptors.

S 47445 is a novel positive allosteric modulator of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors (AMPA-PAM). S 47445 enhanced glutamate's action at AMPA receptors on human and rat receptors and was inactive at NMDA and kainate receptors. Potentiation did not differ among the different AMPA receptors subtypes (GluA1/2/4 flip and flop variants) (EC50 between 2.5-5.4 µM), except a higher EC50 value for GluA4 flop (0.7 µM) and a greater amount of potentiation on GluA1 flop. A low concentration of S 47445 (0.1 µM) decreased receptor response decay time of GluA1flop/GluA2flip AMPA receptors and increased the sensitivity to glutamate. Furthermore, S 47445 (0.1 and 0.3 µM) in presence of repetitive glutamate pulses induced a progressive potentiation of the glutamate-evoked currents from the second pulse of glutamate confirming a rapid-enhancing effect of S 47445 at low concentrations. The potentiating effect of S 47445 (1 µM) was concentration-dependently reversed by the selective AMPA receptor antagonist GYKI52466 demonstrating the selective modulatory effect of S 47445 on AMPA receptors. Using an AMPA-kainate chimera approach, it was confirmed that S 47445 binds to the common binding pocket of AMPA-PAMs. S 47445 did not demonstrate neurotoxic effect against glutamate-mediated excitotoxicity in vitro, in contrast significantly protected rat cortical neurons at 10 µM. S 47445 was shown to improve both episodic and spatial working memory in adult rodents at 0.3 mg/kg, as measured in the natural forgetting condition of object recognition and T-maze tasks. Finally, no deleterious effect on spontaneous locomotion and general behavior was observed up to 1000 mg/kg of S 47445 given acutely in rodents, neither occurrence of convulsion or tremors. Collectively, these results indicate that S 47445 is a potent and selective AMPA-PAM presenting procognitive and potential neuroprotective properties. This drug is currently evaluated in clinical phase 2 studies in Alzheimer's disease and in Major Depressive Disorder.

Synthesis of the butanamide derivative S 19812, a new dual inhibitor of cyclooxygenase and lipoxygenase pathways.

The general synthetic pathway and the interactions with arachidonic acid metabolism of the new compound S 19812 (N-hydroxy-N-methyl 4-(2,3-bis-(4-methoxyphenyl)-thiophen-5-yl)butanamide, CAS 181308-68-9) were investigated. S 19812 was selected for its well balanced dual inhibition of cyclooxygenase and 5-lipoxygenase pathways in vitro in rat polymorphonuclear neutrophils (PMNs) (IC50 PGE2: 0.10 mumol/l, LTB4: 0.07 mumol/l) and ex vivo in mice blood (ED50 PGE2: 13.1 mg/kg, LTB4: 20.8 mg/kg). These properties make this drug a promising therapeutic agent for pain and inflammation associated with osteoarthritis.

General pharmacology of the butanamide derivative S 19812, a new dual inhibitor of cyclooxygenase and lipoxygenase pathways.

S 19812 (N-hydroxy-N-methyl-4-(2,3-bis-(4-methoxyphenyl)-thiophen-5-yl) butanamide, CAS 181308-68-9), a dual inhibitor of cyclooxygenase and lipoxygenase pathways, was evaluated in different models of pain and inflammation. Its gastric tolerance was also investigated. After acute oral treatment S 19812 exhibited a non-opioid analgesic activity observed in the phenylbenzoquinone-induced writhing model in mice (ED50 = 2.1 mg/kg) and in the carrageenan-induced hyperalgesia model in rats (ED50 = 9.1 mg/kg, preventive treatment; 8.3 mg/kg, curative treatment). Anti-inflammatory activity was observed in the adjuvant-induced arthritis in rat (inhibition of edema ED50 = 11 mg/kg/day p.o., day 28). In rats and mice, S 19812 exhibited an excellent gastric tolerance at doses up to 800 mg/kg p.o.