Role of dopamine and selective dopamine receptor agonists on mouse ductus arteriosus tone and responsiveness

Background Indomethacin treatment for patent ductus arteriosus (PDA) is associated with acute kidney injury (AKI). Fenoldopam, a dopamine (DA) DA 1 -like receptor agonist dilates the renal vasculature and may preserve renal function during indomethacin treatment. However, limited information exists on DA receptor-mediated signaling in the ductus and fenoldopam may prevent ductus closure given its vasodilatory nature. Methods DA receptor expression in CD-1 mouse vessels was analyzed by qPCR and immunohistochemistry. Concentration−response curves were established using pressure myography. Pretreatment with SCH23390 (DA 1 -like receptor antagonist), phentolamine (α -adrenergic receptor antagonist) or indomethacin addressed mechanisms for DA-induced changes. Fenoldopam’s effects on postnatal ductus closure were evaluated in vivo. Results DA 1 receptors were expressed equally in ductus and aorta. High-dose DA induced modest vasoconstriction under newborn O 2 conditions. Phentolamine inhibited DA-induced constriction, while SCH23390 augmented constriction, consistent with a vasodilatory role for DA 1 receptors. Despite this, fenoldopam had little effect on ductus tone nor indomethacin- or O 2 -induced constriction and did not impair postnatal closure in vivo. Conclusion(s) DA receptors are present in the ductus but have limited physiologic effects. DA-induced ductus vasoconstriction is mediated via α-adrenergic pathways. The absence of DA 1 -mediated impairment of ductus closure supports the study of potential role for fenoldopam during PDA treatment.