Role of histamine or other released substances in anaphylaxis in isolated guinea pig ileum.

Abstract

A study was made of the role of histamine or other active liberated substances in anaphylaxis in isolated segments of guinea pig ileum. A technique was used by which it can be quantitatively estimated how much of the total anaphylactic reaction is due to liberation of such substances. The method consisted of suspending a segment from a sensitized animal in a 40-ml bath, together with a segment called the ‘indicator segment’, from a normal, nonsensitized animal. Thus, during anaphylactic contraction of the sensitized segment, histamine or any other active substance liberated into the bath would be expected to diffuse through the perfusion bath and cause a contraction of the so-called ‘indicator segment’. The height of the contractions was roughly estimated in terms of that amount of histamine necessary to cause a contraction of the same intensity. Using this technique, it was concluded that no more than 10% of the total anaphylactic contraction in the isolated sensitized guinea pig ileum can be accounted for by histamine or any other substance liberated into the bath fluid.