The effect of enalapril on the renal response to tilting in humans.

Abstract

1. Seventeen normal subjects were tilted on a tilt table and changes in blood pressure, heart rate and renal function were monitored in the absence of drug treatment; the same measurements were repeated during treatment with enalapril in eight of these subjects. 2. In the absence of drug, tilting of the whole body to the 45 degree head up position caused an antidiuresis, antinatriuresis and antikaliuresis; the antinatriuresis resulted from a transient fall in glomerular filtration and from a sustained increase in the tubular reabsorption of sodium, as reflected by a prolonged fall in fractional sodium excretion. 3. Enalapril caused a reduction in blood pressure in the upright position; there was no effect on heart rate. The antinatriuresis of tilt was significantly blunted by enalapril. This resulted from blunting of the transient fall in creatinine clearance and of the increase in tubular sodium reabsorption. Urinary potassium excretion during tilting was not altered by enalapril. 4. These findings are consistent with a direct intrarenal action of angiotensin II, mediating some of the alterations in renal function apparent on assumption of the upright position.

Relationship of the Renin-Angiotensin System and Systemic Arterial Pressure to Sodium Excretion During Atrial Natriuretic Peptide Infusion in Men

“…However, previous work in normal humans has shown that angiotensin converting enzyme inhibition alone blocks the tilt-induced decrease in sodium excretion. 8,9 Therefore, the decrease in sodium excretion observed in the present study with the infusion of enalaprilat during ANP infusion is unlikely to be due solely to the effect of enalaprilat.…”

“…6,7 In addition, studies in normal humans have shown that administration of an angiotensin converting enzyme inhibitor prior to head-up tilt blocks the tilt-induced decrease in urinary sodium excretion. 8,9 Therefore, we considered the possibility that activation of the renin-angiotensin system may have been responsible for the attenuation of sodium excretion observed during ANP infusion and head-up tilt in our previous studies. However, because of the concomitant decrease in arterial pressure during tilt, the independent effect of these two factors on sodium excretion during ANP infusion could not be distinguished in our initial study.…”

Advances in pharmacotherapy: recent developments in the treatment of epilepsy

“…Its slow progress has been primarily dLe to the concern of C N S vacuoles which occurred in some animal species. These vacuoles have not been found in primates nor documented in man (91)(92)(93).…”

“…Conversely, when vigabatrin is stopped, anticonvulsant activity may be prolonged In animals, it takes approximately 6 days to regain maximum enzyme activity when vigabatrin is stopped (90). It was first synthesized in 1974 and subjected to clinical trials in 1979 (91). It is approved for use in the United Kingdom, Ireland, Sweden, Denmark and France.…”