IgE receptor-activated calcium permeability pathway in rat basophilic leukemia cells: measurement of the unidirectional influx of calcium using quin2-buffered cells

Journal Article · Tue Nov 03 04:00:00 EST 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00396a021· OSTI ID:5561376

Fewtrell, C; Sherman, E

The intracellular calcium indicator and buffer quin2 has been used to generate a large calcium buffering capacity in the cytoplasm of rat basophilic leukemia cells. Above 3 mM intracellular quin2, there is no further increase in the initial rate of antigen-induced /sup 45/Ca uptake, suggesting that /sup 45/Ca buffering by quin2 is now sufficient to prevent the immediate efflux of /sup 45/Ca from the cells. Thus, the initial rate of /sup 45/Ca uptake should reflect the true unidirectional influx of calcium that occurs when innumoglobulin E (IgE) receptors are aggregated by antigen. The antigen-induced calcium permeability pathway appears to be saturable, with a K/sub m/ of about 0.7 mM and a V/sub max/ of 0.9 nmol of calcium (10/sup 6/ cells)/sup -1/ min/sup -1/. Although net /sup 45/Ca uptake reaches a plateau a few minutes after antigen stimulation, the increase in plasma membrane permeability is maintained for at least an hour, provided that receptors for IgE remain aggregated. The initial rate of /sup 45/Ca influx correlates well with the subsequent secretion of (/sup 3/H)serotonin in response to different concentrations of antigen. Both /sup 45/Ca uptake and (/sup 3/H)serotonin secretion are maximal when only 10% of the receptors are occupied with antigen-specific IgE. Thus, /sup 45/Ca influx correlates more closely with secretion than with the number of IgE receptors aggregated by antigen.

• Research Organization: Cornell Univ., Ithaca, NY
• OSTI ID: 5561376
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:22; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

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59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
AMINES
ANIMAL CELLS
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
AZOLES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
EVEN-ODD NUCLEI
GLOBULINS
HEMIC DISEASES
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IMMUNOGLOBULINS
INDOLES
INTERMEDIATE MASS NUCLEI
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LEUKEMIA
MAMMALS
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
NEOPLASMS
NEUROREGULATORS
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PERMEABILITY
PROTEINS
PYRROLES
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SECRETION
SEROTONIN
SYMPATHOMIMETICS
TRITIUM COMPOUNDS
TRYPTAMINES
TUMOR CELLS
UPTAKE
VERTEBRATES