Dopaminergic control of sympathetic activity and blood pressure in haemodialysis patients

Bromocriptine was used to test the hypothesis that the abnormality of the dopaminergic system described in haemodialysis patients may cause enhanced sympathetic activity and high blood pressure. Bromocriptine significantly reduced supine mean blood pressure and plasma noradrenaline. Moreover, although the increments in plasma noradrenaline during tilt tests were reduced by bromocriptine there was a significant improvement in the response of blood pressure. These results suggest that dopaminergic control of sympathetic activity may be impaired in haemodialysis patients and may be a cause of high blood pressure. Moreover, a restoration of a normal relationship between noradrenaline and adrenergic receptors would be consistent with the present results.