Na+ channels: Structure, function, and classification

Synthesis, structure-activity relationship of some new anti-arrhythmic 5-arylidene imidazolidine-2,4-dione derivatives

The synthesis of unsubstituted and halogen substituted 5-arylidene basic amide derivatives of imidazolidine-2,4-dione is described. Structural elucidation based on X-ray analysis was performed for four representative compounds. The effect of the studied compounds on the electrocardiogram was examined in vitro in the non-working heart perfusion test and that of an anti-arrhythmic activity in the rat coronary artery ligation-reperfusion model. The most active compound: (5Z)-(3-chloro)benzylidene-3-{2-[4-(hydroxyethyl)piperazin-1-yl]-2-oxoethyl}imidazolidine-2,4-dione has shown properties of the compounds belonging to class Ia, according to the Vaughan Williams classification. Chosen compounds evaluated in vivo were devoid of anticonvulsant and neurotoxical activity.

Effects of log P and phenyl ring conformation on the binding of 5-phenylhydantoins to the voltage-dependent sodium channel

Binding to the neuronal voltage-dependent sodium channel (NVSC) was evaluated for 12 5-phenylhydantoins which systematically varied either log P and/or 5-phenyl ring orientation. The linear correlation of log P with in vitro sodium channel binding activity (log IC50) for hydantoins 1-12 and diphenylhydantoin (DPH) (r2 = 0.638) suggested that simple partitioning into the lipid phase is important but not sufficient to account for the effects of hydantoins on the NVSC. Comparisons among different hydantoins with the same log P but different low-energy phenyl ring orientations revealed that, in addition to log P, the correct 5-phenyl orientation is important for efficient binding.