(from the article `drug`) ...channels in the cell membrane, (2) regulation of cellular activity by way of intracellular chemical signals, such as cyclic adenosine ... In the mid-1970s the calcium channel blockers, another type of antiarrhythmic drug, were introduced. Verapamil and diltiazem are important examples ... Many animal cell...
[n] - ion of calcium
factor IV noun ion of calcium; a factor in the clotting of blood