The proposed research attempts to characterize transport of solutes and water across the epithelium of proximal tubules. A combination of electrophysiological, microperfusion and ultrastructural techniques as well as flux methods will be used. 1. To study the electrical properties of transport systems at the level of the single cell membrane of the epithelium, as well as the electrogenesis of cellular and transepithelial potential differences in the isolated perfused proximal tubule. 2. To study the properties of ion transport systems at specific sites within the epithelium and across specific single plasma membranes, using measurements of changes in ionic activity inside the cell cytoplasm. 3. To study the pathways and compartments within a single proximal tubule epithelium, which contribute to the coupling between solute and solvent flow and which are important for fluid movement. 4. To study the ultrastructual detail of the amphibian proximal tubule and correlate structural membrane components and areas or intraepithelial compartments with transport functions. These studies are performed on amphibian isolated renal tubules because of the size of the cells and the stability of the preparation and as an adequate model which may lead to the understanding of the molecular membrane mechanisms which control salt and water balance in man in health and disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK013844-20
Application #
3225137
Study Section
General Medicine B Study Section (GMB)
Project Start
1976-01-01
Project End
1990-12-31
Budget Start
1989-01-01
Budget End
1990-12-31
Support Year
20
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Yale University
Department
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Abdulnour-Nakhoul, S; Boulpaep, E L (1998) Transcellular chloride pathways in ambystoma proximal tubule. J Membr Biol 166:15-35
Korbmacher, C; Barnstable, C J (1993) Renal epithelial cells show nonselective cation channel activity and express a gene related to the cGMP-gated photoreceptor channel. EXS 66:147-64
Korbmacher, C; Segal, A S; Fejes-Toth, G et al. (1993) Whole-cell currents in single and confluent M-1 mouse cortical collecting duct cells. J Gen Physiol 102:761-93
Korbmacher, C; Boulpaep, E L; Giebisch, G et al. (1993) Endothelin increases [Ca2+]i in M-1 mouse cortical collecting duct cells by a dual mechanism. Am J Physiol 265:C349-57
Ahmad, I; Korbmacher, C; Segal, A S et al. (1992) Mouse cortical collecting duct cells show nonselective cation channel activity and express a gene related to the cGMP-gated rod photoreceptor channel. Proc Natl Acad Sci U S A 89:10262-6
Bock, J F; Boulpaep, E L (1990) Bicarbonate transport mechanisms in the Ambystoma kidney proximal tubule: transepithelial potential measurements. Yale J Biol Med 63:529-47