MemberJune 30, 2020 at 3:30 pm
<div>That is a good insight on your part. It really is a poor explanation isn’t it? Here is my explanation:
§ Blood flow is a balance of forces. Sympathetic stimulation typically has an α<sub>1</sub> receptor effect greater than the β<sub>1</sub> receptor effect, causing vasoconstriction. Muscarinic stimulation will also cause vasoconstriction. ANS stimulation is balanced by the local endothelial cell release of NO, prostaglandins and other substances giving overall vasodilation with an increase in heart rate.
<div>§ With endothelial dysfunction, there is impaired release of local vasodilators, leading to unopposed α<sub>1</sub> receptor effect, or in this case muscarinic stimulation, resulting in vasoconstriction and angina.
<div>· This is the explanation of vasospastic angina (i.e. Prinzmetal angina), which is commonly associated with non-occlusive atherosclerosis.
<div>I hope this helps, Dr T