Blood pressure response to a calcium entry blocker in normotensive subjects with or without a family history of hypertension.

The possibility that a familial background of hypertension might influence the blood pressure response to a calcium entry blocker was evaluated in 15 normotensive relatives of patients with essential hypertension and 18 normotensive subjects with no family history of hypertension. Under control conditions, blood pressure, heart rate, plasma noradrenaline, adrenaline, and renin activity did not differ between the two groups. Nifedipine, at a dose of 10 mg administered sublingually, lowered the blood pressure and increased the heart rate, plasma noradrenaline, and renin activity. The normotensive relatives of patients with essential hypertension did not differ in their responses from the normotensive subjects with no family history of hypertension, with the exception of plasma noradrenaline thirty minutes after nifedipine. These results provide evidence to suggest that there is no functional abnormality with increased dependency of vascular smooth muscle tone on calcium influx in the prehypertensive state.