Ca2+ antagonists in cardiopulmonary changes induced by high altitude hypoxia

Calcium antagonists have been increasingly used in the last decade both as valuable cardiovascular drugs and as tools to investigate the pharmacology of slow channels of many excitable cells. Although very different in chemical structure, all these compounds reduce rather specifically the Ca influx through the voltage dependent Ca channels in cardiac and vascular smooth muscle cells, which results in negative inotropic, chronotropic and dromotropic as well as vasodilating properties of these drugs. Thus, calcium antagonists are successfully used for the treatment of coronary heart disease, arrhytmias and systemic hypertension (1, 2).