Abstract
Essex and Markowitz 1 have made an extensive study of the physiologic action of crotalin and have pointed out a number of similarities to the action of histamine. Feldberg and Kellaway 2 have recently shown that crotalin has the property of liberating histamine into the perfusate when it is added to the per fusion fluid with which the lungs of cats or guinea pigs are being perfused. Their studies demonstrate a mechanism whereby the characteristic action of histamine can be superimposed upon the direct effects of the venom. The extent to which the added action of histamine influences the action of the venom in intact animals is not indicated by these experiments. In a series of studies on anaphylactic shock 3 and peptone shock 4 in the dog, we have been able to show that the degree of the vascular reaction is correlated with and dependent upon the amount of histamine liberated from the dog's tissues in these reactions. We were, therefore interested in determining whether histamine is liberated when venom is administered to the intact dog and whether the amount of histamine liberated is adequate to account for the degree of the vascular effect produced.
Crotalin∗ (from Crotalus atrox) was injected intravenously into 5 anesthetized dogs, in doses of 0.5 to 1.3 mg. per kilo, and samples of blood and thoracic duct lymph were collected during the ensuing reaction and tested for histamine. All of the reactions were severe, 2 being fatal within 20 minutes. Histamine was found in the blood in 2 experiments and also in the lymph in one of these. The identification of histamine was based upon the presence in extracts made by Code's 5 method for the determination of histamine, of a physiologically active substance which lowered the blood pressure of the atropinized cat, contracted the guinea pig intestine, and was inactivated by diazotized sulfanilic acid.
Get full access to this article
View all access options for this article.