The main role of acetylcholine in the cardiovascular system:
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| The main role of acetylcholine in the cardiovascular system |
(1)
Vasodilatation: intravenous injection of small doses of this product may cause a temporary drop in blood pressure due to systemic vasodilation, accompanied by a reflex heart rate. ACh can cause many vasodilatations. Such as the lungs and coronary vessels. Its vasodilator effect is mainly due to inflammatory endothelial cells M, choline receptor subtype, leading to the release of endothelium-dependent relaxation factor (EDRF), nitric oxide (No), which causes relaxation of adjacent smooth muscle cells, possibly through Caused by baroreceptors or chemoreceptors. If the vascular endothelium is damaged, the above effects of ACh will no longer exist, which in turn may cause vasoconstriction. In addition, ACh inhibits the release of NA from noradrenergic nerve endings by activating the presynaptic M1 receptor in sympathetic nerve terminals and is also associated with ACh vasodilation.
(2)
Slow heart rate: also known as negative frequency effect. ACh can delay the auto-depolarization of the sinus node diastolic phase, increase the repolarization current, and prolong the action potential to reach the threshold, resulting in slow heart rate.
