Final answer:
Nitroglycerine promotes vasodilation through the release of nitric oxide, which relaxes the blood vessels allowing for increased blood flow, particularly beneficial in heart disease treatments.
Step-by-step explanation:
Nitroglycerine causes vasodilation of blood vessels due to its effects on levels of nitric oxide. Nitric oxide (NO) acts as a ligand, diffusing across the plasma membrane to interact with receptors in smooth muscle, inducing relaxation and thus vasodilation. This mechanism of nitroglycerine is essential in treatments for heart conditions by facilitating increased blood flow and oxygen delivery.