Abstract
Changes in plasma levels of norepinephrine, blood pressure and pulse rate of 125 patients with vertigo were measured during the orthostatic test. Fifty nine patients (47.2%) showed patterns of orthostatic dysregulation which were evaluated with the following criteria, pulse pressure narrowing of more than 21mmHg (PP+), increase of pulse rate of more than 21 beats per mineute (P+), fall of systolic blood pressure of more than 21mmHg (SP+).
Increases of plasma norepinephrine during the orthostatic test were found in all cases, although greater increases of plasma norepinephrine were found in P+ group. In this P+ group, be it coccompanied by PP+ and/or SP+, the blood pressure was not very responsive to plasma norepinephrine. Thus, it was suggested that disturbance of the adrenergic receptor, manifestation of which includes vasoconstriction, might exist in these patients showing orthostatic dysregulation.
