The role of nitric oxide in the post ischaemic kidney

Post ischaemic renal injury is characterised by a reduction in blood flow to all areas of the kidney. Nitric oxide. synthesized from L-arginine is an important vasodilator in the maintenance of vascular tone, autoregulation and glomerular filtration rate. This study was designed to examine the role of nitric oxide in bringing about the haemodynamic changes seen following reperfusion injury utilising an autoradiographic technique. C-14 iodoantipyrine was used as a tracer to measure intrarenal blood flow in anaesthetised Sprague Dawley rats. Autoradiographs were produced From tissue sections. C-14 concentrations were measured from standards thus allowing blood flow values to be calculated. Ischaemia reperfusion caused reduction in blood flow. This is thought to be due in part to the endothelium being refractory to the vasodilatory action of nitric oxide. Introduction of the nitric oxide inhibitor L-NMMA in control kidneys caused a significant decrease in blood flow. Blocking nitric oxide. however in the presence oi ischaemia reperfusion induced a further reduction in blood flow, indicating that nitric oxide remains important in the maintainance of renal vasodilation during this pathological process.