What is the primary mechanism of action for nitrates in the treatment of angina?

Nitrates primarily work by dilating coronary vessels, which is a critical factor in the treatment of angina. When angina occurs, it is often due to an imbalance between the heart's oxygen supply and demand, frequently exacerbated by narrowed coronary arteries. By dilating these vessels, nitrates increase the blood flow to the heart muscle, providing it with more oxygen. This reduction in oxygen demand and the improvement in blood supply help to alleviate the chest pain associated with angina.

While nitrates can also have effects on heart rate and blood pressure, their primary and most significant action in treating angina is the vasodilation of coronary arteries. This distinction is important in understanding the pharmacodynamics of nitrates and why they are effectively used in managing angina symptoms.