Dopamine in the developing kidney 441 Dopamine in the developing kidney

Abstract

The adult kidney has a high rate of dopamine (DA) production, metabolism, and signalling. The non-neuronal DA system in the adult kidney is of utmost importance for the regulation of salt metabolism. DA may also act as a transcription factor and may be of importance for tissue differentiation. In the central nervous system, D1 receptors require the dopamineand cAMP-regulated phosphoprotein with a molecular weight of 32,000 Dalton (DARPP-32) to mediate their actions. The renal D1 mediates DARPP-32 activation via a cascade involving cAMP and PKA, and protein kinase C (PKC) activation via phospholipase C. Active DARPP-32 has a specific inhibitory effect on protein phosphatase 1 (PP1), leaving, e.g. Na+, K+-ATPase in a phosphorylated, inactive, state. Thus, dopamine acts as a natriuretic hormone in the mature kidney. Here, we discuss the agedependent distribution and some functional aspects of several parts of the renal dopamine system (dopamine, AADC, COMT, D1 receptor, and DARPP-32) during renal morphogenesis.