Norepinephrine transporter function and orthostatic syndromes

Idiopathic orthostatic intolerance and vasovagal syncope are pathophysiologically distinct syndromes of unknown etiology. Both syndromes are associated with orthostatic symptoms. Idiopathic orthostatic intolerance features orthostatic tachycardia due to adrenergic stimulation of the heart. In contrast, in vasovagal syncope, adrenergic stimulation of the heart and the vasculature is acutely withdrawn. The norepinephrine transporter has a pivital role in the regulation of adrenergic tone. This paper reviews recent evidence for the involvement of the norepiphirine transporter and vasovagal syncope, might be assiociated with extreme functional states of the norepiphrine transporter.