- Synthesis and anticonvulsant and neurotoxic properties of substituted N- phenyl derivatives of the phthalimide pharmacophore
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A series of compounds including 4-amino (1), 3-amino (2), 4-nitro (3), 2-methyl-3-amino (4), 2-methyl-3-nitro (5), 2-methyl-4-amino (6), 2-methyl-4- nitro (7), 2-methyl-5-amino (8), 2-methyl-5-nitro (9), 2-methyl-6-amino (10), 2-methyl-6-mitro (11), 2,6-dimethyl (12), 2-methyl-3-carboxy (13), 2- methoxycarbonyl (14), 2-methyl-4-methoxy (15), 2,4-dimethoxy (16), 2-chloro- 4-amino (17), and 2-chloro-4-nitro (18) N-phenyl substituents of phthalimide were evaluated along with N-[3-methyl-(2-pyridinyl)]phthalimide (19), N-(3- amino-2-methylphenyl)succinimide (20), and phenytoin for anticonvulsant and neurotoxic properties. Initial screening in the intraperitoneal (ip) maximal electroshock-induced seizure (MES) test and the subcutaneous pentylenetetrazol-induced seizure (scPtz) test in mice led to the selection of 1, 2, 4, 10, 12, 17, and 19 for oral MES evaluation in rats. The resultant ED50 values for 4, 10, 17, and phenytoin were 8.0, 28.3, 5.7 and 29.8 mg/kg, respectively. In the batrachotoxin affinity assay, IC50 values for 17 and phenytoin were 0.15 and 0.93 μM, respectively, and in the recently validated magnesium deficiency-dependent audiogenic seizure test, ED50 values of 5.2 and 23 mg/kg were obtained for 17 and phenytoin, respectively. Electrophysiology studies on compound 17 point out its ability to (i) potentiate GABA-evoked current responses with a failure to directly activate the GABAA receptor and (ii) to affect, at 100 μM excitatory non NMDA, but not NMDA, receptors with a 25% block of kainate-evoked response. Electrophysiology measurements on voltagegated sodium channels in N1E-115 neuroblastoma cells confirm voltage-dependent block of these channels by compound 17. In view of its interaction with multiple ion channels, one would predict that compound 17 might be active in a wide range of seizure models.
- Vamecq, Joseph,Bac, Pierre,Herrenknecht, Christine,Maurois, Pierre,Delcourt, Philippe,Stables, James P.
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p. 1311 - 1319
(2007/10/03)
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- Design, anticonvulsive and neurotoxic properties of retrobenzamides / N- (nitrophenyl)benzamides and N-(aminophenyl)benzamides
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Design, anticonvulsant properties in maximal electroshock-reduced seizures [MES] and seizures reduced by subcutaneous administration of pentetrazole (scPtz), and neurotoxicity of retrobenzamides (N- (nitrophenyl)benzamides and N-(aminophenyl) benzamides are reported. These data are further compared with those on carbamazepine, phenytoin, ameltolide and other reference compounds. Studies on retrobenzamides in mice dosed intraperitoneally point out a good anticonvulsant potential in the MES test for the amino derivatives (N-(aminophenyl)benzamides) and moderate activity for corresponding 'nitro' derivatives. In rats dosed orally, aminoretrobenzamides were, however, less active in the MES test than in mice dosed intraperitoneally. Differences between experimental animal species and administration routes lead to hypothesize rapid metabolization of compounds, reduced intestinal resorption and increased removal from body. The presence of a methyl substitution on the N-phenyl moiety of aminoretrobenzamides attenuated these discrepancies between mice and rats. Present results indicate that pharmacological values - including the dose offering anticonvulsant protection in 50 % of tested animals (ED50) and protective indices - obtained on some retrobenzamides may compete with phenytoin and carbamazepine values. By contrast with phenytoin, some retrobenzamides further exhibit activity in the scPtz test.
- Bourhim, Mustapha,Poupaert, Jacques H.,Stables, James P.,Vallee, Louis,Vamecq, Joseph
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