The proposed research will be an investigation of the role of cytoplasmic vesicles and their influence on ion transport regulation across ion transporting epithelia. Conventional, ion specific microelectrodes, capacitance measurements, fluctuation analysis and """"""""patch"""""""" clamp methods will be used to measure apical and basolateral membrane potentials, conductances, areas, area changes and single ionic channel properties as well as intracellular ion activities as a function of vesicle fusion effects and pharmacological manipulations to alter vesicle translocation. Measurement of the effect of microfilament and microtubule blocking agents and volume perturbation methods on membrane potentials, resistances and ion activities will be determined to access possible regulation of vesicle translocation. Combined use of cytochalasin B (a microfilament disrupting agent) and colchicin (a microtubule blocking agent) in conjunction with capacitance measurements will allow a determination of these two cytoskeletal structures in vesicle translocation into the apical membrane. Dietary manipulations will be used to determine whether cytoplasmic vesicle density is under hormonal control. Vesicle density is being measured using a newly developed electrical method. Possible vesicle fusion into the basolateral membrane will be measured using antibiotics to reduce apical resistance and volume and stretch regimes to stimulate fusion into the basolateral membrane. An alternate epithelial preparation (the ureters) will be developed to study vesicle translocation. Although the mammalian bladder epithelium translocates vesicles in response to mechanical stimuli other epithelia respond through hormonal interaction. Measurement of toad urinary bladder vesicle translocation and comparison with mammalian bladder will allow a modeling of active and passive vesicle translocation in ion regulation. The results will contribute to the understanding of cytoplasmic vesicles in the regulation of ion transport across epithelia.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK033243-03
Application #
3231636
Study Section
Physiology Study Section (PHY)
Project Start
1984-01-01
Project End
1986-12-31
Budget Start
1986-01-01
Budget End
1986-12-31
Support Year
3
Fiscal Year
1986
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
Jovov, B; Wills, N K; Lewis, S A (1991) A spectroscopic method for assessing confluence of epithelial cell cultures. Am J Physiol 261:C1196-203
Lewis, S A; Clausen, C; Wills, N K (1991) Transport-related modulation of the membrane properties of toad urinary bladder epithelium. Biochim Biophys Acta 1070:99-110
Jungwirth, A; Lewis, S; Lang, F (1991) Kallikrein does not modify the transepithelial potential of rat renal distal convoluted tubules. Nephron 58:225-8
Lewis, S A; Clausen, C (1991) Urinary proteases degrade epithelial sodium channels. J Membr Biol 122:77-88
Jovov, B; Wills, N K; Donaldson, P J et al. (1990) Vectorial secretion of a kallikrein-like enzyme by cultured renal cells. I. General properties. Am J Physiol 259:C869-82
Donaldson, P J; Lewis, S A (1990) Effect of hyperosmotic challenge on basolateral membrane potential in rabbit urinary bladder. Am J Physiol 258:C248-57
Donaldson, P J; Chen, L K; Lewis, S A (1989) Effects of serosal anion composition on the permeability properties of rabbit urinary bladder. Am J Physiol 256:F1125-34
Zweifach, A; Lewis, S A (1988) Characterization of a partially degraded Na+ channel from urinary tract epithelium. J Membr Biol 101:49-56