Effect of shear stress on sup 86 Rb sup + efflux and cytosolic Ca sup 2+ of calf pulmonary artery endothelial cells (CPAEs)
- Rice Univ., Houston, TX (United States) Baylor College, Houston, TX (United States)
The effect of flow-induced shear stress (SS) on membrane K{sup +} permeability and cytosolic free Ca{sup 2+}, (Ca{sup 2+}){sub i}, was investigated by measuring {sup 86}Rb{sup +} efflux and fura-2 fluorescence in CPAEs using a parallel plate flow chamber. Increasing SS from 1 to 2.4, 4.8 or 10 dyn/cm{sup 2} produced a graded, transient increase in {sup 86}Rb{sup +} efflux which peaked within 1 min and subsequently declined rapidly towards pre-stimulus levels. Mathematical modeling confirmed that the transient increase in {sup 86}Rb{sup +} efflux did not reflect a washout phenomenon. Upon returning SS to 1 dyn/cm{sup 2}, {sup 86}Rb{sup +} efflux initially decreased, but returned slowly to basal values. In contrast, application of bradykinin (BK) at a constant SS of either 0.33 or 1 dyn/cm{sup 2} produced a transient increase in {sup 86}Rb{sup +} efflux that was followed by a sustained elevated phase during which time efflux gradually returned to pre-stimulus levels. To determine the mechanism by which shear stress increases K{sup +} permeability, the effect of tetrabutylammonium ion (TBA), a selective inhibitor of Ca{sup 2+}-dependent K{sup +} channels (K{sub Ca}), on both the BK- and SS-induced increases in {sup 86}Rb{sup +} efflux, was examined. TBA inhibited the BK-stimulated increase in {sup 86}Rb{sup +} efflux {gt}90% under both stationary and flow conditions and significantly reduced SS-dependent {sup 86}Rb{sup +} efflux 38.3%. These results suggest that increased {sup 86}Rb{sup +} efflux from CPAEs with SS occurs, at least in part, via K{sub Ca} and suggests that SS increases cytosolic Ca{sup 2+}. However, when measured using fura-2-loaded CPAEs, SS was without significant effect on (Ca{sup 2+}){sub i}.
- OSTI ID:
- 5378573
- Report Number(s):
- CONF-9104107-; CODEN: FAJOE
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 5:4; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM COMPOUNDS
BIOSYNTHESIS
CELL MEMBRANES
PERMEABILITY
POTASSIUM COMPOUNDS
MEMBRANE TRANSPORT
ARTERIES
CALVES
ENDOTHELIUM
FLUORESCENCE
KININS
LUNGS
RUBIDIUM 86
TRACER TECHNIQUES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
CATTLE
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LUMINESCENCE
MAMMALS
MEMBRANES
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
RADIOISOTOPES
RESPIRATORY SYSTEM
RUBIDIUM ISOTOP
RUMINANTS
SYNTHESIS
TISSUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques