Roentgenographic study of ethosuximide-induced functional changes in rat gastrointestinal tract and their modulation by Nivalin in a chronic experiment.

: Ethosuximide, a typical antiabsence drug, causes gastrointestinal complaints in the drug-treated patients. In the present study we investigated in an experimental model the functional disturbances occurring in rat gastrointestinal tract (GIT) after a 100-day chronic administration of ethosuximide. Contrast radiographic study of rat gastrointestinal tract was used. The mechanical activity of GIT smooth muscle (SM) preparations was measured using an in vitro isometric technique. The 100-day ethosuximide treatment induced atonia, disturbed peristalsis, and lead to a delay of the contrast material evacuation from the gastrointestinal tract combined with a reduction of the acetylcholine effect on the contractions of GIT smooth muscles in ethosuximide-treated rats. Nivalin cannot eliminate the ethosuximide-induced disturbances in the gastrointestinal tract after a 100-day administration of ethosuximide to the rats. It is thus assumed that Nivalin is not capable of compensating the inhibiting effect of ethosuximide. The authors assume that desensitization of acetylcholine receptors may occur and this reduces the effect of Nivalin action.