PHY3171 Lecture 18: L18 Sympathetic overactivity + hypertension
10 Feb 2019
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Sympathetic activity to whole body, brain, kidney, heart + impaired nat in the heart. Need to be able to assess sympathetic nerve activity 4 ways to do so: urinary noradrenaline, plasma noradrenaline. Normally following nerve impulse, there is release of noradrenaline and is taken up by the noradrenaline transporters but some leaks out into the blood. If overactive this means that even greater will be leaked out. Therefore, greater urinary or plasma noradrenaline would be indicative of increased sympathetic activation: sympathetic nerve activity recordings: a technique called microneurography (skeletal muscle) Measures how much noradrenaline in plasma or venous outflow how much leaves the tissue. Can measure sympathetic outflow in a number of places depending on where catheter is placed. Total body spill over is compared as well as in kidney in heart. Can also be more noradrenaline in the cleft for longer. Normal physiological response: hpa axis, sympathetic nerves are activated, and levels will go back to normal.
