Which gas is associated with the mechanism of action of nitroglycerin and sildenafil?

Which gas is associated with the mechanism of action of nitroglycerin and sildenafil?

• A. NO
• B. N2O
• C. CO2
• D. NO2

Answer: (A)

Nitric oxide is the signaling gas involved. Nitroglycerin releases NO in vascular smooth muscle, which activates soluble guanylate cyclase and raises cGMP levels, leading to smooth muscle relaxation and vasodilation. Sildenafil doesn’t directly release NO; it slows the breakdown of cGMP by inhibiting phosphodiesterase-5, thus prolonging the NO-induced relaxation. This combination underpins how both drugs produce vasodilation. Other gases like nitrous oxide, carbon dioxide, or nitrogen dioxide do not act as the mediators in this mechanism.

Nitric oxide is the signaling gas involved. Nitroglycerin releases NO in vascular smooth muscle, which activates soluble guanylate cyclase and raises cGMP levels, leading to smooth muscle relaxation and vasodilation. Sildenafil doesn’t directly release NO; it slows the breakdown of cGMP by inhibiting phosphodiesterase-5, thus prolonging the NO-induced relaxation. This combination underpins how both drugs produce vasodilation. Other gases like nitrous oxide, carbon dioxide, or nitrogen dioxide do not act as the mediators in this mechanism.