Role of calcium on excitation-contraction coupling in cardiac and vascular smooth muscle.

The calcium ion is recognized as having a ubiquitous role in a wide range of physiological responses. The calcium entry blockers have assumed a greater role than first thought possible in the management of cardiovascular disorders. As a group, they have multiple effects and can be tailored to meet specific needs. The drugs are well tolerated, thus making them useful for chronic administration. The efficacy of the calcium entry blockers can be enhanced when combined with other therapies such as beta-adrenoceptor antagonists and inhibitors of angiotensin converting enzyme as applied to patients with hypertension, angina pectoris, or both. The range of indications and potential uses of the calcium entry blockers demands an understanding of the role of the slow inward current in cardiac and vascular smooth muscle. This review focuses on the pharmacological actions of the calcium entry blockers and relates these events to their clinical applications in an effort to achieve an understanding of their multiple therapeutic uses.