Aglomerular pathways in intrarenal microvasculature of aged rats

By means of silicone rubber injections, we confirmed the existence of several types of aglomerular arterial pathways within kidneys of aged rats. In superficial cortex some interlobular arteries divide to form aglomerular branches (Ludwig's arterioles) towards cortex corticis. In juxtamedullary cortex these pathways are relatively more numerous, they comprise: (a) Vasa Recta Vera, (b) glomeruli in which afferent and efferent arterioles form a continuous vessel and (c) glomeruli with two efferent vessels, one by-passing glomerular tuft. In addition, results obtained in the rat by the microsphere technique are in agreement with our morphological observations.