Vascular-tubular relationships in the mammalian kidney

Comments

This “chapter” presents pictures that illustrate the basic organization of the mammalian kidney, based on the unipapillary kidney of the rabbit and the rat, two species widely used in renal physiology (before the era of transgenic animals which put the mouse on the front of the scene).

It is important to underline that the complexity of the structure of the mammalian kidney is largely linked to the adaptations allowing the production of urine of higher osmotic pressure than the body fluids and thus to the ability to save water for the excretion of soluble waste. Among mammals, and especially among rodents, wide quantitatives, but also sometimes qualitative differences are observed, that are related to a higher capacity to concentrate urine. The type of diet (herbivorous, omnivorous, or carnivorous) is also associated with different types of renal adaptations.

Important features of the organization of the mammalian kidney, illustrated in this chapter are as follows:

1. Hairpin shape of the loops of Henle and medullary vessels, favoring counter current exchanges of water and solutes.

2. Compartmentalization of the vascular environment of the different parts of the nephron allowing isolation of some zones from others.

2.a. Vertical compartmentalization (along the axis of the nephrons): cortex and different zones and subzones of the medulla (see pictures 1 to 8).

2.b. Horizontal compartmentalization resulting, in the cortex, from the alternance of medullary rays and labyrynthic zones (pictures 13 to 16), and in the inner stripe of the outer medulla, from the alternance between vascular bundles and interbundle capillary plexuses (pictures 20 to 25)

Staining with Alcian Blue

Alcian blue was infused in vivo by an intravenous route. Kidneys were then removed and dehydrated in alcoohol. Then, the renal tissue was cleared by impregnation with methylsalycilate.

Vascular filling with Microfil Silicone Rubber®

The renal vasculature has been filled post mortem with white silicone rubber (Microfil Silicone Rubber®) through either the renal artery or the renal vein. Kidneys were then removed and dehydrated in alcoohol. Then, the renal tissue was cleared by impregnation with methylsalycilate.

Histological sections

The pictures of histological sections were kindly provided by Wilhelm KRIZ ( Anatomy and Developmental Biology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany) and Brigitte KAISSLING (Institute of Anatomy, University of Zurich, Zurich, Switzerland).

See more detailed description of these techniques in the following papers:

1. Bankir L, Hollenberg NK: In vivo staining of the kidney with Alcian Blue : an adjunct to morphological and physiological studies. Renal Physiol 6: 151-155, 1983
2. Bankir L, Kaissling B, Rouffignac-de C, Kriz W: The vascular organization of the kidney of Psammomys obesus. Anat Embryol 155: 149-160, 1979
3. Bankir L, Rouffignac-de C: Urinary concentrating ability : Insights from comparative anatomy (Editorial review). Am. J. Physiol. 249 (Regulatory Integr. Comp. Physiol. 18): R643-R666, 1985