Enhancement of the anaphylactoid reaction in rats by phenylalanine enamine.

Low doses of phenylalanine enamine, administered at the same time as dextran, significantly enhanced the onset, height and duration of the anaphylactoid reaction in rats. The enhancement occurred after intraperitoneal or local administration. The enamine did not modify the histamine or 5-hydroxytryptamine responses in rat paws, so its effect on dextran may be due to modification of the release mechanism of the two amines from tissue mast cells.