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Dopamine receptor subtypes in renal brush border and basolateral membranes
C C Felder1, A M McKelvey, M S Gitler
1Department of Pediatrics, Georgetown University Medical Center, Washington, DC.
Kidney International
|August 1, 1989
Summary
Dopamine receptors, specifically DA-1 and DA-2, are present in both brush border and basolateral membranes of canine kidney proximal tubules. These receptors influence sodium transport and cellular signaling pathways.
Area of Science:
- Nephrology
- Molecular Pharmacology
- Cell Biology
Background:
- Dopamine (DA) is known to modulate renal tubular sodium transport.
- Previous studies indicated DA receptors in proximal tubules, but subtypes in brush border membrane (BBM) and basolateral membrane (BLM) were undetermined.
Purpose of the Study:
- To determine the presence and characteristics of dopamine receptor subtypes (DA-1 and DA-2) in canine kidney BBM and BLM.
- To investigate the functional coupling of these receptors to intracellular signaling pathways.
Main Methods:
- Quantitation of DA-1 and DA-2 receptors using radioligand binding assays with specific antagonists.
- Analysis of receptor binding kinetics and affinity using Rosenthal plots and non-linear regression.
- Assessment of adenylate cyclase and phospholipase-C activity in response to DA receptor agonists/antagonists.
Main Results:
- Both DA-1 and DA-2 receptors were identified in canine kidney BBM and BLM with saturable, reversible binding.
- High and low affinity binding sites for DA-1 receptors and suggestive evidence for DA-2 receptors were found in both membranes.
- DA-1 receptor activation increased adenylate cyclase and phospholipase-C activity, with greater effects in BLM than BBM.
Conclusions:
- Canine kidney BBM and BLM possess both DA-1 and DA-2 receptors.
- Renal DA-1 receptors are functionally linked to the stimulation of adenylate cyclase and phospholipase-C activity.