Final answer:
Nitroglycerin relieves cardiac-related chest discomfort by dilating coronary arteries, owing to the release of nitric oxide, which relaxes the smooth muscle of the coronary vessel walls and increases blood flow.
Step-by-step explanation:
Nitroglycerin relieves cardiac-related chest pain primarily by dilating coronary arteries. This effect is attributed to its role in triggering the release of nitric oxide (NO), a paracrine chemical that functions as a potent vasodilator. The release of NO causes the smooth muscle within the walls of the coronary vessels to relax, subsequently increasing blood flow to the heart muscle and alleviating pain associated with angina.
Nitroglycerin's capacity to dilate coronary arteries and improve blood flow is crucial for treating conditions such as stable angina, where pain occurs due to exertion and is alleviated by rest or nitroglycerin administration. Its usage in the immediate treatment of myocardial infarction (MI) is a testament to its effectiveness in restoring blood flow and relieving chest discomfort caused by ischemia.