Calcium-channel blockers and asthma.

Calcium-channel blockers and asthma The concentration of free calcium ions (Ca++) in the cytoplasm regulates many aspects of cell function, including muscle contraction and the secretion of mediators, neurotransmitters and hormones. Con- traction of airway smooth muscle, secretion of mast cell mediators and mucus, and vagal neurotransmis- sion, all of which may be increased in asthma, are dependent on movement of Ca++ into the cell. This raises the possibility that an increase in Ca++ flux may be a fundamental abnormality in asthma and might be an explanation for bronchial hyperreactivity.' The development of drugs that interfere with the entry of Ca++ into cells has now made it possible to study the role of Ca++ in disease, and these drugs are widely used in the treatment of cardiovascular disease. There has recently been increasing interest in the use of calcium-channel blockers in asthma, not because of their therapeutic potential but because of what they may reveal about underlying mechanisms.