Related Experiment Videos
Renal and systemic hemodynamics in sustained essential hypertension
Insights
Essential hypertension in men is linked to reduced renal blood flow (RBF), which is partly reversible with certain medications. This reduction correlates with blood pressure and adrenergic system activity.
Area of Science:
- Cardiovascular Physiology
- Nephrology
- Pharmacology
Background:
- Essential hypertension is a prevalent condition affecting cardiovascular and renal health.
- Reduced renal perfusion is a potential complication of sustained hypertension.
- The role of the adrenergic system in hypertension-related renal dysfunction requires further elucidation.
Purpose of the Study:
- To investigate cardiac output (CO), renal blood flow (RBF), and other hemodynamic parameters in hypertensive men.
- To determine the relationship between RBF, blood pressure, age, and dopamine beta hydroxylase (D beta H) activity.
- To assess the reversibility of reduced RBF with specific antihypertensive agents.
Main Methods:
- Studied 198 men (131 hypertensive, 67 controls) measuring CO, RBF, calf blood flow (CBF), hepatic blood flow (HBF), glomerular filtration rate (GFR), and D beta H activity.
- Analyzed correlations between RBF/CO ratio, age, blood pressure, and D beta H activity.
- Administered clonidine, alpha-methyldopa, and propranolol to assess their effects on RBF.
Main Results:
- Hypertensive men exhibited significantly decreased RBF and RBF/CO ratio (p < 0.001).
- RBF and RBF/CO ratio were negatively correlated with age, blood pressure, and D beta H activity (p < 0.01).
- Clonidine and alpha-methyldopa reversed the RBF reduction (p < 0.01), while propranolol did not.
Conclusions:
- Reduced renal perfusion in essential hypertension is partly reversible.
- Adrenergic system abnormalities contribute to decreased RBF in hypertensive individuals.
- Pharmacological interventions targeting the adrenergic system can improve renal perfusion in hypertension.
Abstract:
Cardiac output (CO), renal blood flow (RBF), calf blood flow (CBF), and hepatic blood flow (HBF), glomerular filtration rate (GFR), and dopamine beta hydroxylase (D beta H) activity were studied in 198 men (67 normotensive controls and 131 hypertensive patients) of the same age with sustained uncomplicated essential hypertension. In the hypertensive men, the RBF and the RBF/CO ratio were significantly decreased (p less than 0.001). The RBF and RBF/CO ratio were negatively correlated with age (p less than 0.01), blood pressure (p less than 0.01), and D beta H activity (p less than 0.01). None of these relationships were observed with CBF and HBF. The observed decreases in RBF and the RBF/CO ratio in hypertensive men were reversed after administration of clonidine and alpha-methyldopa (p less than 0.01), but not after administration of propranolol. The study provides evidence that the reduction of renal perfusion in essential hypertension is partly reversible and related to an abnormality in the adrenergic system control.