Evaluation of neurogenic control of blood pressure in hypertension 'with tetraethylammonium and spinal

The contribution of sympathetic constrictor im-pulses to arteriolar tone is now recognized as play-ing an important though sometimes variable role in the maintenance of increased peripheral re-sistance in some patients with hypertension. How-ever, lack of a clear understanding of the exact nature of autonomic influences and of their im-portance in relation to other pressor factors has complicated the development and evaluation of therapeutic measures for hypertension which have as their aim the modification of the "neurogenic component. " 3 Results obtained after surgical sympathectomy have seemed encouraging in cer-tain patients, discouraging in others. It has be-come apparent that operative results are incon-sistent and that the most striking inconsistency is the effect on the blood pressure. Difficult, too, is the choice of patients who may be expected to benefit from this type of treatment; no satisfactory method of selection has yet been suggested. This study was undertaken in an effort to eval-uate the nature of autonomic influences on blood pressure level as indicated by observations and comparisons of the responses to autonomic block-ade with tetraethylammonium chloride 4 (TEAC) and spinal anesthesia to high thoracic levels. MATERIAL AND METHODS Twenty-four patients were included in the study. Eleven patients had malignant and 13 had benign hyper