MOA of Nitroglycerine 

  1. Nitroglycerine converted to NO (Active Metabolite) 
  2. NO bonds with Guanylyl cyclase and catalyzes the conversion of GTP to cyclic GMP.
  3. cGMP induces the enzyme Myosin LC phosphatase 
  4. Myosin-LC phosphatase dephosphorylates the phosphorylated myosin-LC (Contraction) to Myosin-LC (Relaxation) 

Reducing Preload: Vasodilation promotes peripheral pooling of blood and decreases venous return to the heart, reducing preload. This results in decreased myocardial oxygen demand.

Reducing Afterload: Arteriolar relaxation reduces systemic vascular resistance and arterial pressure, also known as afterload. This decreases the resistance the heart must overcome to eject blood, which reduces the workload of the heart. 





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