GI pharmacology of polyethyleneimine II: motor activity in anesthetized dogs

The effects of orally and intravenously administered doses of polyethyleneimine were observed in 18 chloralose-urethan-anesthetized dogs. Polyethyleneimine produced an initial augmentation of rhythmic segmenting gastric antral contractions, a copious flow of gastric mucus, increased segmenting and propulsive activities of the small and large intestines, and occasional micturition and defecation. The gastric corpus and fundic regions became relaxed and enlarged. These events were associated with the prompt appearance of retching. The retching response to oral administration could only be abolished by bilateral vagotomy or bilateral sympathectomy. The skeletal muscle component of retching was blocked by tubocurarine. Intravenous administration of chlorpromazine blocked the retching response and gastric corporal atonia to either intravenous or oral doses of polyethyleneimine. Either oral or intravenous administration of polyethyleneimine produced no detectable changes in the lead II ECG but was associated with marked transient reductions in both mean and pulsatile arterial blood pressures. These depressor effects showed clear tachyphylaxis. In all cases where GI effects were noted, respiration was augmented and erratic in a manner associated with the retching responses.