Mediators in anaphylaxis of guinea-pig small intestine.

With the use of a nonsensitized segment serving as indicator, the release of histamine or other substances during anaphylactic contraction in the isolated sensitized guinea-pig ileum was demonstrated (1). Histamine release in anaphylaxis was measured by immersing sensitized guinea-pig tissues including the small intestine in Tyrode solution containing the antigen (2,3). Attempts to demonstrate directly the release of 5-hydroxytryptamine (5HT) from the sensitized guinea-pig ileum have been unsuccessful (4,5). In most of these studies histamine and 5-HT were assayed biologically. Biological assay requires great skill in techniques. The purpose of the present experiment is to determine spectrophotofluoro metrically the possible release of histamine and 5-HT from the sensitized isolated guinea-pig small intestine by antigen, as first studies regarding the effect of various drugs on the release of mediators.