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Effect of dopamine2 blockade on renal function under varied sodium intake
S Bughi1, E Jost-Vu, I Antonipillai
1University of Southern California, Los Angeles 90033.
Summary
The dopamine-2 receptor (DA2) influences renal blood flow (RBF), with its role changing based on sodium intake. Dopamine activation of DA2 receptors contributes to RBF regulation, modulated by salt balance.
Area of Science:
- Nephrology
- Cardiovascular Physiology
- Pharmacology
Background:
- Dopamine (DA) receptors, including DA1 and DA2, are present in renal vasculature.
- The specific role of DA2 receptors in human renal blood flow (RBF) regulation and their interaction with sodium balance remains unclear.
Purpose of the Study:
- To investigate the function of the dopamine-2 receptor (DA2) in controlling human RBF.
- To determine how variations in sodium intake affect DA2 receptor activity in the kidney.
Main Methods:
- Seven healthy males received a low-dose dopamine infusion.
- A selective DA2 receptor blocker, domperidone (DOM), was administered alone and with dopamine.
- Systemic and renal hemodynamics were measured noninvasively; urinary prostacyclin was quantified.
Main Results:
- Dopamine infusion increased RBF and prostacyclin, an effect reduced by low salt intake.
- Domperidone alone decreased basal RBF during normal and low salt diets but not high salt.
- Domperidone did not affect prostacyclin excretion across different salt intakes.
Conclusions:
- Both DA1 and DA2 receptors are activated by dopamine in renal vessels.
- DA2 receptors play a significant role in the vasodilatory effects of dopamine on RBF.
- Sodium balance dynamically alters the coordinated actions of DA1 and DA2 receptors in regulating RBF.