Examining the effects of NPRA antagonist anantin on sci-induced ployuria.

Abstract

Polyuria, or the over production of urine, is a prevalent condition that significantly impacts the quality of life in individuals suffering from a spinal cord injury (SCI). Post-SCI induced polyuria is thought to have been associated with altered levels of vasopressin (AVP), atrial natriuretic peptide (ANP), and natriuretic peptide receptor A (NPRA). In the present study, the function of NPRA was analyzed in the rat contusion model using anantin, an NPRA antagonist. A daily dose of either 100 µg of anantin or vehicle was administered intraperitoneally immediately following the SCI surgery and continued until termination, 4 weeks post injury (wpi). The animals were housed in metabolic cages for a 24-hour period every week to measure urine and drink volumes. Other assessments included mean arterial pressure (MAP) and serum potassium/sodium concentrations. Metabolic cage data showed a significant increase in void volume regardless of treatment when compared to pre-injury baselines. There was a significant decrease in MAP post-SCI, which was significantly less for anantin-treated rats. Further, there was a significant decrease in serum sodium and no change in serum potassium across all groups. Taken together, these results indicate that targeting NPRA alone may not be an effective intervention, and further targets should be investigated to provide a more cohesive understanding of SCI-induced polyuria.