How do nitrates relax smooth muscle?
How do nitrates relax smooth muscle?
Organic nitrates and related compounds, in particular sodium nitroprusside, are direct vascular smooth muscle relaxants, via an increase in intracellular cGMP. Nitroprusside vasodilates both arterial and venous vascular smooth muscle equally. Nitroglycerin appears to preferentially act as a venous vasodilator.
How does nitric oxide cause vascular smooth muscle relaxation?
stimulates a cGMP-dependent protein kinase that activates myosin light chain phosphatase, the enzyme that dephosphorylates myosin light chains, which leads to smooth muscle relaxation.
How do organic nitrates cause vasodilation?
Organic nitrates are potent vasodilators and are the most widely used antianginal agents during acute events. They selectively dilate epicardial coronaries and also enhance collateral flow; they also inhibit platelet aggregation.
What is the mechanism of action of GTN?
Mechanism of action Glyceryl trinitrate, an organic nitrate, is a vasodilator. Its principal pharmacological action is the relaxation of vascular smooth muscle. Glyceryl trinitrate produces a dose related dilation of both arterial and venous beds. Venous dilation predominates over dilation of the arterioles.
Do nitrates decrease preload or afterload?
Nitrates decrease myocardial preload and, to a lesser extent, afterload. Nitrates increase venous capacitance and induce venous pooling, which decreases preload and myocardial oxygen demand. Direct vasodilation of coronary arteries may increase collateral blood flow to the ischemic myocardium.
How does nitric oxide cause vasodilation?
Nitric oxide is a compound produced by many cells of the body. It relaxes vascular smooth muscle by binding to the heme moiety of cytosolic guanylate cyclase, activating guanylate cyclase and increasing intracellular levels of cyclic-guanosine 3′,5′-monophosphate, which then leads to vasodilation.
What is the role of nitric oxide in muscle relaxation?
Nitric oxide (NO) is a mediator of vasodilation in blood vessels. It is induced by several factors, and once synthesized by eNOS it results in phosphorylation of several proteins that cause smooth muscle relaxation.
How does nitric oxide work as a vasodilator?
As a vasodilator, nitric oxide signals the blood vessels to relax, allowing them to expand. This effect allows blood, nutrients, and oxygen to flow freely to every part of your body. But when nitric oxide production is decreased, your health can become compromised.
Does nitroglycerin reduce preload or afterload?
Nitroglycerin reduces left ventricular afterload through arterial dilation as well as preload through venous dilation. This effect on afterload is not apparent from measurement of pressure in the brachial artery.
How does nitroglycerin work in the body?
Nitroglycerin is in a class of medications called vasodilators. It works by relaxing the blood vessels so the heart does not need to work as hard and therefore does not need as much oxygen.
How do organic nitrates work?
Organic nitrates are efficacious drugs for treatment of angina pectoris attacks, acute coronary syndromes, pulmonary edema, and hypertensive crisis. They work by releasing nitric oxide (NO•) or a NO•-related compound (eg, nitrosothiols).
Why do nitrates decrease preload?
Coronary. Although organic nitrates can dilate both arteries and veins, venous dilation predominates when these drugs are given at normal therapeutic doses. Venous dilation reduces venous pressure and decreases ventricular preload.