The Occurrence of a Lipid‐Soluble Smooth‐Muscle Stimulating Principle (‘SRS’) in Anaphylactic Reaction

Chakravarty, N. The occurrence of a lipid‐soluble smooth‐muscle stimulating principle (‘SRS’) in anaphylactic reaction. When tissues from sensitized guinea pigs are incubated with antigen, there is a diffusion of histamine and a lipid‐soluble, smooth‐muscle stimulating principle (‘SRS’) into the incubation fluid. ‘SRS’ is soluble in ether and other organic solvents and is of acid nature. The time curves of histamine and ‘SRS’ are similar except for the slower appearance of ‘SRS’ in the first few minutes. There is a close correlation between the amounts of histamine and ‘SRS’ obtained from different tissues. Moreover, with increasing concentrations of antigen the amounts of both histamine and ‘SRS’ rise proportionally. The observations are compatible with the view that the two smooth‐muscle stimulating substances may originate from a common source.