In vitro studies of the coronary arteries of man and swine as demonstrated by a new technic, angioplethysmokymography.

A new in vitro technic for the study of isolated surviving arteries and veins is described. Observations of the reactivity of 21 human and 68 swine coronary arteries to histamine, acetylcholine, l-epinephrine and l-norepinephrine are reported. Histamine and acetylcholine uniformly caused vasoconstriction of the coronary arteries of man and swine. Three potential mechanisms of coronary artery vasoconstriction in these species are suggested. The blocking action of antihistaminic drugs on vasoconstriction due to histamine, and of atropine on vasoconstriction due to acetylcholine is demonstrated. It is suggested that combined therapy with these drugs may be useful in treatment of diseases of the coronary arteries.