Action of Synthetic Lysine Polypeptides on Isolated Guinea Pig Ileum.

Summary L-lysine polypeptides stimulated contraction of freshly excised guinea pig ileum. Ileal segments were refractory to a second challenge of polylysine, and the antihistamine, Benadryl, blocked the action of the polypeptide. Consequently, the contraction was attributed to release of endogenous histamine or a histamine-like substance which was displaced by the basic polypeptide. Polylysyl histamine was synthesized by initiation of polymerization of ∊-carbobenzoxy-N-carboxy-L-lysine anhydride with histamine. Although polylysyl histamine was readily hydrolyzed by trypsin. The relationship of these data to the proteolytic theory of histamine release was discussed.