Measurement of the internal pH of mast cell granules using microvolumetric fluorescence and isotopic techniques

Journal Article · Wed Apr 01 00:00:00 EST 1987 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(87)90098-1· OSTI ID:6409268

De Young, M B; Nemeth, E F; Scarpa, A

The intragranular pH of isolated mast cell granules was measured. Because of the minute amounts of isolated granules available, two techniques were developed by modifying aminoacridine fluorescence and (/sup 14/C)methylamine accumulation techniques to permit measurements with microliter sample volumes. Granule purity was demonstrated by electron microscopy, ruthenium red exclusion, and biochemical (histamine, mast cell granule protease) analysis. The internal pH was determined to be 5.55 +/- 0.06, indicating that the pH environment within mast cell granules is not significantly different from that of previously studied granule types (i.e., chromaffin, platelet, pancreatic islet, and pituitary granules). Collapse of the pH gradient by NH+4 was demonstrated with both techniques. No evidence of Cl-/OH- or specific cation/H+ transport was found, and major chloride permeability could not be unequivocably demonstrated. Ca/sup 2 +/ and Cl- at concentrations normally present extracellularly destabilized granules in the presence of NH+4, but this phenomenon does not necessarily indicate a role for these ions in the exocytotic release of granule contents from intact cells. The pH measurement techniques developed for investigating the properties of granules in mast cells may be useful for studying other granules that can be obtained only in limited quantities.

• Research Organization: Case Western Reserve Univ. School of Medicine, Cleveland, OH
• OSTI ID: 6409268
• Journal Information: Arch. Biochem. Biophys.; (United States), Vol. 1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
MAST CELLS
PH VALUE
CARBON 14 COMPOUNDS
FLUORESCENCE
MEASURING METHODS
METHYLAMINE
RATS
RESPONSE MODIFYING FACTORS
TRACER TECHNIQUES
AMINES
ANIMAL CELLS
ANIMALS
CONNECTIVE TISSUE CELLS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LUMINESCENCE
MAMMALS
ORGANIC COMPOUNDS
RODENTS
SOMATIC CELLS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques