Dopamine D1 receptor within Angiotensin II type 1 receptor (AT1R)–Dopamine D1 receptor (D1R) heterodimer (AT1R–D1R heterodimer)

The Dopamine D1 receptor (D1R) within the AT1R–D1R heterodimer is a specialized G protein-coupled receptor complex primarily located in the renal proximal tubule cells (Zeng et al., 2003, PMID: 12819235). This heterodimer is essential for the counter-regulatory control of sodium excretion, where D1R activation normally inhibits the sodium-retaining effects of the Angiotensin II type 1 receptor (AT1R) (Gildea et al., 2014, PMID: 24610802). In conditions such as salt-sensitive hypertension, the functional interaction between these two receptors is often disrupted or uncoupled, leading to impaired natriuresis and increased systemic blood pressure (Armando et al., 2015, PMID: 25602530). Drugs like the D1R agonist fenoldopam and AT1R antagonists like candesartan interact with this complex to modulate renal function and blood pressure. The heterodimer exhibits unique pharmacological properties, such as allosteric cross-talk, where the binding of a ligand to one receptor protomer alters the signaling or affinity of the partner receptor. Targeting this specific heteromeric interface represents a novel therapeutic approach for treating cardiovascular and renal diseases by restoring physiological sodium balance and reducing oxidative stress.

Other names

D1R-AT1R heteromerAT1R-D1R complexDopamine D1-Angiotensin II type 1 receptor heteromerD1R-AT1R heterodimer

The mechanism involves allosteric cross-talk and functional antagonism within the heterodimer complex; specifically, the activation of the Dopamine D1 receptor (D1R) protomer leads to the heterologous desensitization and inhibition of the Angiotensin II type 1 receptor (AT1R) protomer, thereby reducing sodium reabsorption in the renal proximal tubule (PMID: 12819235, 24610802).