Neuronal nitric oxide synthase, nNOS, regulates renal hemodynamics in the postnatal developing piglet.

Introduction: Nitric oxide (NO) vasodilation critically modulates renal hemodynamics in the neonate compared with the adult. Based on the postnatal expression pattern of renal neuronal nitric oxide synthase (nNOS), the hypothesis was that nNOS is the major NOS isoform regulating renal hemodynamics in the immature, but not mature, kidney.

Results: NOS inhibitors did not alter mean arterial pressure (MAP) in either group.

Angiotensin II regulates NOS expression in afferent arterioles of the developing porcine kidney.

NO protection is crucial against angiotensin II (ANG II) mediated vasoconstriction in postnatal preglomerular resistance vessels. Although whole kidney NOS is developmentally regulated, NOS regulation in developing renal resistance vessels is unknown. The hypothesis was NOS expression and function in developing afferent arterioles are regulated by ANG II through AT1 and AT2 receptors.

Nitric oxide synthase and renin-angiotensin gene expression and NOS function in the postnatal renal resistance vasculature.

Nitric oxide (NO), produced by nitric oxide synthase (NOS), critically counteracts angiotensin-II-enhanced vascular resistance in the immature kidney, perhaps due to the developmental regulation of NOS expression and function in the postnatal preglomerular resistance vessels (PRV). Our experiments measured the messenger ribonucleic acid (mRNA) gene expression of neuronal NOS (nNOS), endothelial NOS (eNOS), and components of the renin-angiotensin system (renin, AT1 and AT2 receptors), by real-time RT-PCR, as well as NOS enzymatic activity by citrulline assay in PRVs (afferent, interlobular, and arcuate arterioles) obtained from swine ages newborn, 7 and 21 days, and adult. NOS enzymatic activity was upregulated in PRVs immediately after birth but decreased to adult levels with maturation.

Glomerular eNOS gene expression during postnatal maturation and AT1 receptor inhibition.

Glomerular maturation increases from immature superficial to advanced juxtamedullary nephrons, while nephrogenesis continues postnatally in porcine kidneys. Endothelial NOS, eNOS, shows significant postnatal renal developmental regulation, perhaps mediated by Angiotensin II (AII). The objective was to compare eNOS mRNA gene expression between superficial and juxtamedullary glomeruli obtained from piglets and adult pigs utilizing laser capture microdissection during basal conditions and, to determine the role of the AII AT1 receptor, AT1, after chronic AT1 inhibition (AT1X) with candesartan.