EVALUATION OF NEUROGENIC AND HUMORAL FACTORS IN BLOOD PRESSURE MAINTENANCE IN NORMAL AND TOXEMIC PREGNANCY USING TETRAETHYLAMMONIUM CHLORIDE

Abstract

Blood pressure responses to the intraven. injn. of tetraethylammonium chloride (TEAC) were measured in 10 normal non-pregnant controls, in the prepartum and postpartum periods of 10 patients at term of normal pregnancy, and in 23 patients with toxemia of pregnancy both during and following recovery of toxemia. The TEAC blood pressure response and floor were found to deviate strikingly and consistently from the normal, both in toxemia of pregnancy and in normal pregnancy at term. In toxemia the floor is consistently elevated and falls to normal following recovery. In normal term pregnancy the floor is depressed and rises to normal following parturition. Since TEAC, by blocking the autonomic nervous system at the ganglia, eliminates neuro-genic tone but does not lessen humoral tone, the results suggest that: the hypertension of toxemia of pregnancy is supported by an excessive degree of humoral tone; the blood pressure in normal term pregnancy is maintained largely by neurogenic and intrinsic mechanisms; and clinical assay with TEAC may be a helpful aid in diagnosis of toxemia of pregnancy and in the evaluation of changes in severity during its course.