BLOOD-BORNE VASOTROPIC SUBSTANCES IN EXPERIMENTAL SHOCK

Abstract

A variety of animals subjected to acute and graded hemorrhage (dogs and rats), hind-limb tourniquet (dogs, cats and rabbits), trauma in the Noble-Collip drum (rats) and leg-pounding (dogs), developed blood borne vasotropic substances. The effect of the substances was detected in samples of blood (serum or heparinized plasma) taken from the animals in various stages of shock by injecting the samples into the tail vein of normal rats. The effect observed was a change in the intensity and duration of the reactivity of the terminal vessels in the exposed meso-appendix to the topical application of epinephrine. A vasoexcitor material (VEM) appeared early after blood-loss and during all stages of rapid exsanguination (I-11/2 hrs. in dogs). When the loss of fluid was prolonged, the VEM was replaced by vasodepressor material (VDM). The VDM became increasingly effective during the development of irreversibility of the shock syndrome. The appearance of a marked VDM effect was found to be correlated with the fatal outcome of the shock syndrome.