Some aspects of calcium pharmacology

Calcium has a dual role in the regulation of cell function It carries charge and thus contributes to the changes of membrane potential in excitable cells, and it acts as a biochemical messenger by directly binding to proteins and modifying their functional state. Proteins directly or indirectly affected by calcium are very diverse and include enz mies, cy-toskeletal proteins, ion channels, and transcription factors. 

Calcium-dependent processes relevant to pharmacological intervention mainly include pace-making in the heart, and contraction in heart and smooth muscle. These are affected by dmgs that either act on calcium channels directly, or on other receptors that will have some downstream effect on the cytosolic availability of calcium. Exemples are the p-and ttj-adrenergic receptors (see below). 

Calcium has a pivotal role in the control of muscle cell action. Muscle cells occur in different types  

Heart and skeletal muscle together are classified as striated muscle yet do have some important functional differences (see below). The muscle cells in vessel walls control the blood pressure, which makes them important dmg targets that heart muscle cells are important targets, too should go without saying. 

While actin and myosin are present and responsible for motility in essentially all cells, a peculiarity of the striated 

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