Back to Search
Start Over
Morphological and functional characteristics of the kidney of cartilaginous fishes: with special reference to urea reabsorption
- Source :
- American journal of physiology. Regulatory, integrative and comparative physiology. 307(12)
- Publication Year :
- 2014
-
Abstract
- For adaptation to high-salinity marine environments, cartilaginous fishes (sharks, skates, rays, and chimaeras) adopt a unique urea-based osmoregulation strategy. Their kidneys reabsorb nearly all filtered urea from the primary urine, and this is an essential component of urea retention in their body fluid. Anatomical investigations have revealed the extraordinarily elaborate nephron system in the kidney of cartilaginous fishes, e.g., the four-loop configuration of each nephron, the occurrence of distinct sinus and bundle zones, and the sac-like peritubular sheath in the bundle zone, in which the nephron segments are arranged in a countercurrent fashion. These anatomical and morphological characteristics have been considered to be important for urea reabsorption; however, a mechanism for urea reabsorption is still largely unknown. This review focuses on recent progress in the identification and mapping of various pumps, channels, and transporters on the nephron segments in the kidney of cartilaginous fishes. The molecules include urea transporters, Na+/K+-ATPase, Na+-K+-Cl−cotransporters, and aquaporins, which most probably all contribute to the urea reabsorption process. Although research is still in progress, a possible model for urea reabsorption in the kidney of cartilaginous fishes is discussed based on the anatomical features of nephron segments and vascular systems and on the results of molecular mapping. The molecular anatomical approach thus provides a powerful tool for understanding the physiological processes that take place in the highly elaborate kidney of cartilaginous fishes.
- Subjects :
- Fish Proteins
Salinity
Physiology
Renal urea handling
Cartilaginous fish
Biology
chemistry.chemical_compound
Osmoregulation
Species Specificity
Physiology (medical)
medicine
Animals
Urea
Seawater
Kidney
urogenital system
Fishes
Membrane Transport Proteins
Nephrons
Adaptation, Physiological
Renal Reabsorption
medicine.anatomical_structure
chemistry
Biochemistry
Adaptation
Subjects
Details
- ISSN :
- 15221490
- Volume :
- 307
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- American journal of physiology. Regulatory, integrative and comparative physiology
- Accession number :
- edsair.doi.dedup.....19e8c900c11bb69ae4a39b6268bb1e64