Effects of inositol trisphosphate on calcium mobilization in high-voltage and saponin-permeabilized platelets
Interest in phosphatidylinositol metabolism has been greatly stimulated by the findings that diglyceride and inositol phosphates may serve as second messengers in modulating cellular function. Formation of 1,4,5-inositol trisphosphate (IP/sub 3/), in particular, has been linked to mobilization of intracellular calcium in a number of cell types. The authors have examined the ability of IP/sub 3/ to mobilize calcium in human platelets permeabilized by either saponin or high-voltage discharge. Saponin at 15 ..mu..g/ml effectively permeabilized platelets to exogenous inositol 1,4,5-trisphosphate which released bound (/sup 45/Ca) within 1 min and with a Ka of 7.4 +/- 4.1 ..mu..M. A small (25%) azide-sensitive pool was also responsive to inositol trisphosphate. The calcium pools were completely discharged by A-23187 and the ATP-dependent uptake was prevented by dinitrophenol. In contrast to the result with saponin, platelets accessed by high-voltage discharge were insensitive to challenge by inositol 1,4,5-trisphosphate. The data suggest that while inositol 1,4,5-trisphosphate can rapidly mobilize platelet calcium, the ability to demonstrate this depends on the method of permeabilization.
- Research Organization:
- Univ. of Virginia, Charlottesville
- OSTI ID:
- 5322865
- Report Number(s):
- CONF-8604222-; TRN: 86-028308
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BLOOD PLATELETS
PERMEABILITY
CALCIUM
MEMBRANE TRANSPORT
INOSITOL
BIOLOGICAL EFFECTS
METABOLISM
ATP
CALCIUM 45
PHOSPHATES
SAPONINS
TRACER TECHNIQUES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CALCIUM ISOTOPES
CARBOHYDRATES
DAYS LIVING RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
GLYCOSIDES
INOSITOLS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MATERIALS
METALS
MONOSACCHARIDES
NUCLEI
NUCLEOTIDES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
RADIOISOTOPES
SACCHARIDES
550201* - Biochemistry- Tracer Techniques