Relative bioactivity of histamine and slow reacting substance of anaphylaxis released during anaphylactic reaction from different tissues of guinea pigs and rats.

ABSTRACT

Relative amount of histamine and SRS-A released during Schultz Dale reaction were indirectly estimated. Percent block produced by specific antagonists, mepyramine and FPL 55712, on antigen induced response in various tissues was compared with controls. The relative bioactivity of histamine and SRS-A released was 93% and 7%, respectively, in rat lungs 37% and 63% in guinea pig lungs; 82% and 18% in guinea pig intestine, 59% and 41% in rat intestine and 100% and 0% in skin of guinea pig and rats. Expectedly, individual experiments showed gross variations because anaphylaxis is rarely dose related.