Evidence for NOS-containing renal neuronal somata transiently expressing a catecholaminergic phenotype during development in the rat.

Transiently catecholaminergic cells (TC-cells) expressing tyrosine hydroxylase (TH) have been shown in a variety of tissues during embryonic life. To investigate the possible relationship of nitric oxide synthase (NOS)-containing renal neuronal somata (RNS) and the TC-cells, we examined serial 100 microm slices of whole kidneys for TH-immunofluorescence and NADPH-d histochemistry during prenatal and postnatal development. The number of TH-cells increased during the prenatal period, peaked at birth and were very rare by PD21. A subpopulation of TH-immunoreactive RNS displayed NADPH-d activity. By PD21 the TH-positive RNS had practically disappeared while the number of NADPH-d positive RNS was markedly increased. These results suggest that kidneys possess transient catecholaminergic cells which display NOS-activity and that NOS expression may be the end-point in the differentiation of the RNS.