ABSTRACT
The possible release of cardioinhibitory factors from the small intestine during severe hemorrhagic shock was examined by testing arterial and intestinal venous plasma samples obtained at various stages during the experiment in two groups of anesthetized dogs. One group of dogs was subjected to arterial hypotension at 35 +/- 5 mmHg for 3 h followed by reinfusion of all shed blood, while the other group was treated alike except that there was no hemorrhagic hypotension. The plasma samples were assayed for cardioinhibitory activity by utilizing the Langendorff guinea pig heart preparation. None of the plasma samples obtained from the sham operated dogs significantly alter the performance of the guinea pig heart. The arterial sample taken during the compensation phase of hemorrhagic hypotension increased, while the arterial and intestinal venous plasma taken at the terminal stage decreased the dP/dt. Plasma Na+, K+, total Ca2+, and Mg2+ concentration of all samples were within normal limits. It is concluded that the small intestine releases cardioinhibitory factors in severe hemorrhagic shock.
