THE EFFECTS OF ANAPHYLAXIS, AND OF HISTAMINE, UPON THE CORONARY ARTERIES IN THE ISOLATED HEART.

Anaphylaxis in the isolated, perfused hearts of cats has been shown to be accompanied by a considerable, though transient, increase in coronary flow. This result is contrasted with that observed in the hearts of guinea pigs and rabbits in which the coronary arteries are constricted during anaphylaxis. Attention is directed to the fact that, in the hearts of these three species, the effects of anaphylaxis and of histamine are qualitatively parallel. The characteristic anaphylactic response in the isolated hearts of guinea pigs has been evoked: (a) in the organs removed from immune animals, (b) by each of two antigens (horse serum and egg albumen) under conditions of double sensitization, and (c) upon exposure of the hearts of passively sensitized animals to the type-specific polysaccharide of the pneumococcus. It is evident that, among the effects of anaphylaxis upon smooth muscle in various organs, there must be considered that upon the coronary arteries.