Arterial
hypertension and
arteriosclerosis are dramatic consequences of vascular
calcium overload. Acute intracellular
calcium overload of vascular smooth muscle cells produces hypercontractility.
Hypertension develops if a general increase in systemic arteriolar tone leads to a rise in peripheral flow resistance. Moreover, progressive elevation of
calcium destroys the structural integrity of the arterial and arteriolar walls. Thus, in various animals models,
calcium overload initiates lesions of an arteriosclerotic character. Interestingly, conventional human coronary plaques also represent a
calcium-dominated type of
arteriosclerosis. With the advent of specific
calcium antagonists, the pathogenic effects of
calcium overload and its deleterious consequences have become, for the first time, accessible to therapeutic intervention. Accordingly, adequate treatment with
calcium antagonists prevents
calcium overload and can thereby protect arteries and arterioles from functional disturbances and structural damage. In spontaneously hypertensive rats, specific
calcium antagonists of the
verapamil,
nifedipine and
diltiazem type normalise blood pressure (BP) by reducing transmembrane
calcium influx into vascular smooth muscle cells. However, in addition to controlling BP, these drugs also act as tissue
protective agents. The long term effects of
calcium antagonists such as
verapamil in experimental
hypertension include the prevention of severe
arteriosclerosis, myocardial
hypertrophy, and malignant
nephrosclerosis. In humans, the
antihypertensive efficacy of
verapamil is well documented. Further clinical studies have yet to evaluate the antiarteriosclerotic and tissue protective potential of
verapamil in humans.