ABSTRACT
The main functions of calcium ion are the following: regulates muscle contraction, regulates the release of many neurotransmitters and hormones, and regulates/controls permeability of cell membranes to other ions. The reason why can use calcium-channel blockers to control cardiac dysfunction without affecting skeletal muscle function is that the source of calcium ion for muscle contraction varies between the three muscle types: heart muscle, vascular smooth muscle, and skeletal muscle. There are major differences in the uses and safety margins between the three main types of calcium blocker - the nifedipine group, verapamil and diltiazem. The best theory is that after cardiac contraction, the calcium ion which entered the muscle fibre at the start of contraction must be pumped out again, into both the extracellular fluid and the cardiac intracellular calcium store. T-calcium channels are present mainly in the cardiac conducting tissue. Understanding different calcium-channel blockers helps the prescriber to select the optimal drug in each patient.
