Nutritional Factors in Hemodynamics

Conclusions and Summary

1. As compared to pair fed controls, guinea pigs on a vit. C free diet showed no obvious differences in blood pressure or in ability to respond in pressure manner to intravenous or intra-arterial injections of epinephrine at the doses employed. 2. The animals were bled by a standard procedure of hemorrhage. Avitaminosis C was accompanied by a significant reduction in the survival time, in resistance to anesthesia, and in the ability to withstand comparable amounts of blood loss. In addition, all deficient animals, with one exception, were unable to elaborate renal VEM as determined by rat assays of the plasma. 3. The significance of these observations is discussed. The suggestion is offered, in relation to earlier findings, that the larger arterioles with undiminished constrictor responses to epinephrine in avitaminosis C may function primarily in maintaining normotension and in producing the vasoconstrictor component of acute pressor reactions. The smaller, terminal arterioles, with greatly diminished epinephrine reactivity during vitamin C deficiency, may act chiefly in the pressor mechanism to supplement the larger vessels in acute stress states and during prolonged attempts at blood pressure elevation.