[Clinical significance of plasma catecholamines in autonomic nerve diseases]

Although it was well known that noradrenaline was secreted from the terminal of sympathetic nervous system, we supposed that plasma noradrenaline does not always indicate sympathetic nervous activity. This was the reason, why we need at least 10 ml of plasma for noradrenaline measurement and so, many plasma sample could not be collect continuously from the same person, 15 years ago. Now, plasma noradrenaline was be analyzed from 0.05 ml of plasma for single isotope radioenzymatic assay. Blood samples of noradrenaline measurements could be collected through venous catheter inserted in cubital vein every 20 min 24 hours. We can study the relationship between circadian rhythm of plasma noradrenaline and that of blood pressure, etc.