Age dependent expression and distribution of nitric oxide (NO) synthase isoforms in the ovine kidney

Devin W Davis,Wei Qi,Megan L Lewis,David A Hart,Francine G Smith

doi:10.4236/ojmip.2013.32010

Devin W Davis, Wei Qi + Show 3 more

Open Access

https://doi.org/10.4236/ojmip.2013.32010

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Abstract

The aim of the present study was to measure intrarenal spatial and temporal localization of all three nitric oxide synthase (NOS) isoforms in the developing ovine kidney. Reverse transcriptase-polymerase chain reaction (RT-PCR), Western Blot analyses, and in situ hybridization techniques were performed for NOS I -III isoforms in renal tissue obtained from sheep aged ~24 h, one, three, six, and 12 weeks post natally (N = 3). RT-PCR performed on cortical and medullary kidney tissue revealed the presence of all three NOS isoforms from day one to 12 weeks postnatally. NOS I and NOS II mRNA levels were greater in cortex compared to medulla during the first three weeks whereas NOS III mRNA levels were predominantly transcribed within the medulla. In all NOS isoforms, there was a decrease in cortical mRNA levels after three to six weeks. Protein levels confirmed the presence of all three NOS isoforms over the first three months of postnatal life. By demonstrating NOS isoform transcripts to be more abundant in the early post natal period, these findings may provide insight into the age dependent role of NO in modulating kidney function during ontogeny.

Highlights

The endothelial derived relaxing factor, nitric oxide (NO), is a gaseous free radical that functions as an endogenous mediator of a variety of physiological processes
In previous studies carried out in conscious, chronically instrumented lambs, we provided evidence that some of the physiological effects of NO are developmentally regulated [2,3,4]: Administration of the L-arginine analogue, NG-nitro-L-arginine methyl ester, L-NAME, which prevents NO production from nitric oxide synthase (NOS) isoforms, is associated with age-dependent effects on renal hemodynamics and function: After treatment with L-NAME, there is a marked increase in renal vascular resistance (RVR), which is greatest at one-week, and least at six weeks, post natally [3]
NOS II mRNA levels were higher in cortex than medulla during the first three weeks post natally; both cortical and medullary levels decreased after three weeks (Figure 1(b))

Summary

Introduction

The endothelial derived relaxing factor, nitric oxide (NO), is a gaseous free radical that functions as an endogenous mediator of a variety of physiological processes. In previous studies carried out in conscious, chronically instrumented lambs, we provided evidence that some of the physiological effects of NO are developmentally regulated [2,3,4]: Administration of the L-arginine analogue, NG-nitro-L-arginine methyl ester, L-NAME, which prevents NO production from NOS isoforms, is associated with age-dependent effects on renal hemodynamics and function: After treatment with L-NAME, there is a marked increase in renal vascular resistance (RVR), which is greatest at one-week, and least at six weeks, post natally [3]. In lambs aged ~six weeks, proximal fractional Na+ reabsorption decreases after L-NAME administration, resulting in a prompt natriuresis; in contrast, there are no effects on proximal fractional Na+ reabsorption at one-week These findings demonstrate that, in conscious lambs, endogenously produced NO modulates glomerular and tubular function in an age-dependent manner [5]

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