EurekaMag.com logo
+ Site Statistics
References:
53,214,146
Abstracts:
29,074,682
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Role of inner medullary collecting duct sodium chloride transport in urinary concentration






American Journal of Physiology 249(5 PART 2): F688-F697

Role of inner medullary collecting duct sodium chloride transport in urinary concentration

Mathematical modeling with simulation techniques were used to analyze the role of medullary collecting duct NaCl transport in the urinary concentrating process. The mathematical model incorprated experimentally determined epithelial transport parameters and anatomical parameters obtained chiefly from experiments in rabbit kidneys. The simulations predict that solute concentration profiles along the medullary collecting ducts are highly sensitive to the rate and pattern of active NaCl absorption along the length of the collecting duct system. When active NaCl absorption was assumed to be zero in the outer medullary collecting duct and to increase along the inner medulla to a very high value at the papillary tip, the simulated solute concentration profiles in the medullary collecting ducts as well as relative concentrations between different inner medullary structures agreed well with experimental data. However, despite optimal choice of collecting duct transport parameters and the use of experimentally determined permeability coefficients, only modest total solute gradients could be generated axially in the inner medullary interstitium, and passive luminal dilution did not occur in the thin ascending limb. We conclude: (1) Axial heterogeneity of transport properties along the inner medullary collecting duct must be assumed to explain in vivo findings from micropuncture and microcatheterization studies. (2) Active NaCl transport from the inner medullary collecting ducts is important chiefly for efficient conservation of NaCl rather than for concentration of solutes in the renal inner medulla. (3) Important inconsistencies exist between several previously reported experimental observations and the theoretical requirements for passive luminal dilution in the thin ascending limb of Henle's loop.

(PDF 0-2 workdays service: $29.90)

Accession: 006351055



Related references

Role of inner medullary collecting duct NaCl transport in urinary concentration. American Journal of Physiology 249(5 Pt 2): F688-F697, 1985

Factors governing sodium and chloride transport across the inner medullary collecting duct. Kidney International 38(4): 654-667, 1990

Effect of volume expansion on sodium and chloride transport along the inner medullary collecting duct of the rat. Kidney International 16(6): 806, 1979

Sodium and chloride transport along the inner medullary collecting duct: effect of saline expansion. American Journal of Physiology 238(6): F504-F508, 1980

Atrial peptide and cyclic gmp effects on sodium chloride transport in inner medullary collecting duct. American Journal of Physiology 259(2 PART 2): F258-F268, 1990

Expression and role of sodium, potassium, chloride cotransport in mouse inner medullary collecting duct epithelial cells. Pfluegers Archiv European Journal of Physiology 443(1): 123-131, October, 2001

Simulation of the profile of water, sodium chloride and urea transport in the countercurrent multiplication system between thin ascending limb and inner medullary collecting duct. Tohoku Journal of Experimental Medicine 168(1): 47-62, 1992

Prostaglandin E2 role in alpha-2 inhibition of water, sodium and urea transport in rat inner medullary collecting duct. FASEB Journal 13(5 PART 2): A728, March 15, 1999

Modulation of vasopressin dependent urea transport in rat inner medullary collecting duct by peritubular sodium chloride and urea. Clinical Research 37(2): 580A, 1989

Expression and role of sodium, potassium, chloride cotransport (NKCC1) in mouse inner medullary collecting duct (mIMCD-K2) epithelial cells. Pflugers Archiv 443(1): 123-131, 2001