title: Immunomorphometric study of rat renal inner medulla.
abstract: We utilized immunofluorescent immunolabeling of renal tissue sections to identify and count tubules at specified depths of the rat renal inner medulla. We used primary antibodies to aquaporin-1 (AQP1; labeling thin descending limbs), aquaporin-2 (AQP2; labeling inner medullary collecting ducts), the rat kidney-specific chloride channel (ClC-K1; labeling thin ascending limbs), and von Willebrand factor (labeling descending vasa recta). Secondary antibodies conjugated to different fluorophores were used, giving up to a three-color display. Labeled structures were then identified and counted. At each level sampled in the inner medulla, many more thin limbs were labeled by ClC-K1 than AQP1. In addition, thin limbs were found to label with antibodies to ClC-K1 on both sides of their hairpin turns. We conclude that the descending thin limbs shift from expressing AQP1 to expressing ClC-K1 some distance before the point where they turn and begin to ascend. Mathematical models can use our quantitative data to explore implications for the urine-concentrating mechanism.
authors.affiliation: Mathematical Research Branch, National Institutes of Health, Bethesda, Maryland 20892-2690, USA. ray@helix.nih.gov
authors.forename: Raymond
authors.initials: R
authors.lastname: Mejia
authors.forename: James B
authors.initials: JB
authors.lastname: Wade
mesh_terms: D000818:Animals; D000906:Antibodies; D051398:Aquaporin 1; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins / Q000032:analysis* / Q000276:immunology; D002645:Chickens; D018118:Chloride Channels / Q000032:analysis* / Q000276:immunology; D005455:Fluorescent Antibody Technique; D007671:Kidney Concentrating Ability / Q000502:physiology; D007679:Kidney Medulla / Q000737:chemistry* / Q000166:cytology; D008138:Loop of Henle / Q000737:chemistry / Q000166:cytology; D008297:Male; D011817:Rabbits; D051381:Rats; D011910:Rats, Brattleboro; D014841:von Willebrand Factor / Q000032:analysis / Q000276:immunology
chemical_list: D000906:Antibodies; C496022:Aqp1 protein, rat; C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D018118:Chloride Channels; C082118:Clcnka protein, rat; D014841:von Willebrand Factor; D051398:Aquaporin 1