Chapter 45 – Dopamine Mechanisms in the Kidney

Publisher Summary This chapter focuses on dopamine mechanisms in the kidney and physiologic interactions of the renal dopaminergic system and the rennin–angiotensin system (RAS). Renal dopamine (DA) biosynthesis in the kidney occurs in proximal tubule cells (PTC) as a result of uptake of filtered L-dihydroxyphenylalanine (L-DOPA) by way of a sodium (Na+) transporter in the apical membrane. The renal D1-like receptor family plays a major role in the regulation of tubule Na+ transport. The natriuretic action of DA is due to inhibition of both proximal and distal tubule Na+ reabsorption. In addition to direct modulation of renal tubule Na+ transport, DA affects renin release from renal JG cells via the D1-like receptor family. Renal DA serves as one of several paracrine mediators of renal Na+ excretion. During low Na+ intake, Na+ is retained to meet the body's requirement for Na+ homeostasis. Under these conditions, the RAS is stimulated and DA biosynthesis is markedly curtailed, both leading to antinatriuresis.