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Ethanol-induced acute gastric ulceration (EIGU) is widely studied. ATP dependent potassium channel (KATP) modulators are thought to interfere with some physiologic functions of the stomach. We have studied the effects of different doses of KATP modulators (diazoxide as agonist and glibenclamide as antagonist) on EIGU in rats. Gastric lesions were quantified. Fasting blood glucose (FBS) levels were measured enzymatically. EIGU was prevented by diazoxide and aggravated by glibenclamide. Diazoxide increased and glibenclamide decreased FBS respectively. The present study shows that KATP modulators are involved in the production of EIGU with a mechanism which remains to be elucidated.

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It has been reported that some of H1 receptor antagonists have important effects on cardiovascular system. Terfenadine as a non-sedative H1 receptor antagonist has an arrhythmogenic activity. In this study we have shown the effects of four antihistamine drugs: terfenadine, loratadine, clemastine and diphenhydramine, on the rate and contractions of isolated rat atria. Terfenadine (1-10 µM) caused a negative chronotropic effect (19.5-80%) and arrhythmia after 10 min. followed by a decrease in the contractile force by (7.5%), and finally after 45 min. asystolia occurred. Loratadine (30-150 µM) decreased the rate of contractions (10-82%) after 10 min. the contractile force of atria was decreased (10-19%) after 20 min. Loratadine did not produce any arrhythmia. Diphenhydramine (5-20 µM) produced bradycardia (14.5-43%) after 20 min and decreased the contractile force (2.5-40%) after 40 min. Clemastine (3-10 µM) produced negative chronotropic and inotropic effect by (11.5-42%) and (10-58%) respectively. These findings indicate that all four drugs caused bradycardia and reduced contractile force, but in the case of terfenadine, it also had arrhythmogenic activity. Loratadine had the least cardiotoxic effect.