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Intracellular calcium in essential hypertension. A parameter for assessing effective antihypertensive treatment
Insights
The loop diuretic piretanide reduced intracellular calcium and increased sodium in hypertensive patients. This effect may be linked to reduced blood pressure via diuretic-induced hypovolaemia suppressing humoral factors.
Area of Science:
- Cardiovascular Pharmacology
- Nephrology
- Cell Physiology
Background:
- Essential hypertension is characterized by elevated blood pressure.
- Intracellular ion concentrations, particularly sodium (Na+) and calcium (Ca2+), play a role in vascular tone regulation.
- Diuretics are a cornerstone in hypertension management, but their precise cellular mechanisms require further elucidation.
Purpose of the Study:
- To investigate the impact of the loop diuretic piretanide on blood pressure.
- To assess the effects of piretanide on intra-erythrocytic free Na+ and Ca2+ levels in patients with essential hypertension.
- To explore the potential role of diuretic-induced hypovolaemia in mediating antihypertensive effects.
Main Methods:
- A study involving 14 essential hypertensive patients.
- Measurement of intra-erythrocytic free Na+ and Ca2+ activity.
- Experiments using spontaneously hypertensive rats (SHRs) to investigate the humoral transmission of hypertension.
Main Results:
- Piretanide treatment led to a significant decrease in intra-erythrocytic Ca2+ activity (P < 0.01).
- Intra-erythrocytic Na+ activity showed a significant increase following piretanide administration (P < 0.05).
- In SHRs, hypovolaemia was found to abolish the humoral transmission of hypertension to normotensive rats.
Conclusions:
- Piretanide effectively modulates intracellular ion balance in hypertensive individuals.
- The observed decrease in intracellular Ca2+ may contribute to reduced vascular tone under diuretic therapy.
- Diuretic-induced hypovolaemia might suppress humoral factors, mediating the antihypertensive effects of piretanide.
Abstract:
The effects of the loop diuretic piretanide on blood pressure and intra-erythrocytic free Na+ and Ca2+ were examined in 14 essential hypertensives. Intra-erythrocytic Ca2+ activity was found to decrease (P less than 0.01) and Na+ activity to increase (P less than 0.05). In spontaneously hypertensive rats (SHRs) hypovolaemia abolished the humoral transmission of hypertension to normotensive rats. Therefore the decrease in intracellular Ca2+, which may be responsible for the diminished vascular tone under diuretic treatment, could be mediated by a suppression of humoral factors due to diuretic-induced hypovolaemia.