Studies of Anaphylaxis in the Albino Rat with Reference to Diet and Histamine

Abstract

Summary and Conclusions In 42 albino rats sensitized to horse serum or egg albumen by large multiple doses, only 2 failed to show some observable signs or pathological changes of anaphylactic shock. However, the individual variation in susceptibility was great. In general, shock was clinically more striking in small or malnourished rats, while in adults the in vivo signs might be entirely lacking and yet the pathological changes be typical. A bread diet did not increase the susceptibility to shock. The pathological changes of anaphylactic shock in the rat consist of venous congestion, edema, hemorrhage, and eosinophilia, being most extensive in the upper intestinal tract. In some instances at least, the typical pathology of experimental asthma was produced. Specific Dale uterine reactions could not be obtained, although occasional non-specific contractions were noted. Histamine in a dilution of 1:7500 caused a good, sustained contraction of the excised uterus, whereas a dilution of 1:1,000,000 produced relaxation of tone and inhibition of rhythmicity as reported by others. Rats uniformly produce precipitins when large, multiple doses of horse serum or egg albumen are administered. The measurable weight of the rat's adrenal gland is unaffected by shock or bread diet.