Plasma catecholamines in Down's syndrome, at rest and during sympathetic stimulation.

Five adult female patients with Down's syndrome were compared with five age-matched controls in the standing and cold pressor tests. In both tests, there were no differences between the two groups in heart rate, systolic and diastolic blood pressure or plasma noradrenaline, adrenaline and dopamine concentrations. However, plasma adrenaline tended to be higher in the Down's group, both in the standing and the cold pressor tests.