Determination of norepinephrine apparent release rate and clearance in humans

摘要: A method for estimating the rate of entry norepinephrine into plasma (norepinephrine apparent release rate) and clearance from in humans is presented. The procedure involves intravenous infusion tritiated l-norepinephrine, sufficiently high specific activity to avoid elevating blood pressure, until plateau concentration reached plasma, measurement under steady state conditions. In ten normal subjects at rest, was 0.54 ± 0.20 μg/m2/min. (mean standard deviation). It significantly lower four patients with idiopathic peripheral autonomic insufficiency, 0.19 0.12 μg/m2/min., but latter, despite reduced release, near because slowed circulation, 1.69 0.44 l/min. compared 2.80 0.73 (p<0.05). given uptake inhibitor, desipramine, slow removal again neurotransmitter higher than would be expected existing norepinephrine. findings suggest that methods which measure dynamic processes quantify sympathetic nervous better measurements alone.