IgE receptor-activated calcium permeability pathway in rat basophilic leukemia cells
When antigen-stimulated /sup 45/Ca uptake is measured in RBL cells loaded with > 3 mM quin2, re-extrusion of /sup 45/Ca is minimized and the initial rate of /sup 45/Ca uptake reflects the true unidirectional influx of Ca. This influx correlates more closely with secretion than with the number of IgE receptors aggregated by antigen. The antigen-induced permeability pathway is saturable, having a Km of about 0.7 mM and a Vmax of 0.9 nmol Ca/10/sup 6/ cells/min and it persists for at least an hour provided that receptor aggregation is maintained. The negatively charged fluorescent probe bis-oxonol is insensitive to changes in the mitochondrial membrane potential and is, therefore, a useful plasma membrane potential indicator. Antigen-stimulation of RBL cells equilibrated with bis-oxonol causes a rapid depolarization that peaks within 2-3 minutes and persists until receptor aggregates are disrupted. Antigen-induced depolarization is seen in the absence of extracellular calcium, but is almost completely abolished when both sodium and calcium are replaced by glucose. Addition of calcium restores this response even when sodium is absent. This suggests that the IgE receptor-activated permeability pathway has a similar conductance for sodium and calcium ions.
- Research Organization:
- Cornell Univ., Ithaca, NY
- OSTI ID:
- 5498330
- Report Number(s):
- CONF-8604222-; TRN: 86-026531
- 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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CALCIUM
MEMBRANE TRANSPORT
CELL MEMBRANES
PERMEABILITY
IMMUNOGLOBULINS
RECEPTORS
ANTIGENS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL PATHWAYS
CALCIUM 45
LEUKEMIA
MITOCHONDRIA
RATS
TRACER TECHNIQUES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DISEASES
ELEMENTS
EVEN-ODD NUCLEI
GLOBULINS
HEMIC DISEASES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
METALS
NEOPLASMS
NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques