Isradipine (also known as DynaCirc or Prescal) is a calcium channel blocker within dihydropyridine (DHP) class that can be used for treating high blood pressure and essential hypertension. There are at least 5 different types of calcium channels in human which are L-, N-, P/Q-, R- and T-type. Isradipine only targets the L-type that mediate muscle cell contraction by binding for stabilizing their inactive conformation. Inactivated calcium channel are more frequent in smooth muscle cells because of longer depolarizations. This pathway demonstrates the binding of isradipine on arterial smooth muscle cells inhibits the influx of calcium ions, which lead to decreased arterial smooth muscle contractility and subsequent vasoconstriction. Calcium ion enters the cell and bind to calmodulin, and then calcium-bound calmodulin binds and activates myosin light chain kinase (MLCK). Activated myosin light chain kinase (MLCK) can phosphorylate subunit of myosin, which is an important step for muscle contraction. Therefore, binding and inhibiting of calcium channels can lead to inhibition of influx of calcium that result in decreased contractile activity (vasodilation). Vasodilatory effects can reduced the blood pressure.

Isradipine Pathway References

Striated Muscle Contraction References