"β-Adrenergic Stimulation Increases Cellular Uptake of Potassium: Increased secretion of catecholamines, especially epinephrine, can cause movement of potassium from the extracellular to the intracellular fluid, mainly by activation of β2-adrenergic receptors." Or does this mean that the stimulation causes a direct intake of potassium ions FROM THE PLASMA INTO THE CARDIAC CELLS, hence causing a less negative membrane potential and an easier firing of an action potential? This information is from the medical physiology Guyton and Hall textbook, page 384, put into my own words if I have understood it correctly. So now since the sympathetic nervous system increases the heart rate, then why does this beta adrenergic stimulation occur? It would decrease the heart rate, so what is happening? This, consequently, makes it more difficult for an action potential to fire, and as a result, a decrease in the heart rate. Thus, a more negative membrane voltage will arise as the potassium ions flow out of the cardiac muscle cells more easily due to the more steep ionic gradient set. Since β-Adrenergic stimulation increases cellular uptake of potassium, this will reduce the plasma concentration of potassium.
Nur Ahmed Asks: How does the SNS increase the heart rate when it causes an increase in cellular uptake of potassium?
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