Altered dopaminergic modulation of sympathetic nervous system activity in idiopathic edema.

Hormonal and mean arterial pressure responses to posture and isometric handgrip exercise were examined in 6 women with idiopathic edema and 10 age- and weight-matched normal women before and after 5-7 days of administration of the dopamine agonist, bromocriptine (2.5 mg three times a day). Edema patients demonstrated greater orthostatic weight gain, greater upright epinephrine values, and greater supine and upright norepinephrine values than did the control group. However, supine and upright plasma dopamine levels were similar in the two groups. In edema patients there was a greater supine and posture related norepinephrine and epinephrine to dopamine ratio than in normal controls. These abnormalities were not corrected by treatment with bromocriptine. Supine and upright plasma norepinephrine and epinephrine levels were decreased following bromocriptine treatment in normal subjects but not in edema patients. These data are consistent with the concept that there is decreased dopaminergic regulation of sympathetic nervous activity in patients with idiopathic edema.