Assessment of neuronal uptake of noradrenaline in humans: defective uptake in some patients with essential hypertension.

1. Disappearance of tritiated noradrenaline from plasma, after infusion to steady-state, was studied to assess neuronal uptake of noradrenaline inessential hypertension. 2. Plasma tritiated noradrenaline disappearance was biexponential. Rapid removal was dependent on neuronal uptake, being slowed both in normal subjects after desipramine, and in patients with sympathetic nerve dysfunction (autonomic insufficiency). 3. In nine of thirty-eight hypertensive patients the t1/12 similarly was prolonged. Endogenous noradrenaline escaping uptake after release, and spilling over into plasma, was increased in these patients. 4. Defective neuronal uptake of noradrenaline, by exposing adrenergic recepotors to high local transmitter concentration, may be important in the pathogenesis of essential hypertension in some patients.