Chemotaxis of newt eosinophils: calcium regulation of chemotactic response
KeywordsAmino Acid Sequence; Animals; Caffeine; Calcium; Chemotactic Factors, Eosinophil; Chemotaxis, Leukocyte; Chromatography, Gel; Cobalt; Egtazic Acid; Eosinophils; Fluorescent Dyes; Fura-2; Ionomycin; Molecular Sequence Data; Neomycin; Salamandridae; Verapamil
Medicine and Health Sciences
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AbstractLocal chemical events underlying chemotaxis were characterized in a new model cell, the newt eosinophil. These cells exhibit a chemotactic response to a trypsin-sensitive component of newt serum. Ca2+ plays a role in this process, since treatments expected to diminish Ca2+ availability from the medium [ethylene glycol-bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, Co2+, and verapamil], to break down transmembrane Ca2+ gradients (ionomycin), or to interfere with the function of intracellular Ca2+ stores (caffeine and neomycin) inhibited cell polarization and movement. Using imaging techniques we found that cytosolic Ca2+ concentration ([Ca2+]i) increased in response to newt serum. Migrating newt eosinophils exhibited a dynamic heterogeneous distribution of [Ca2+]i. [Ca2+]i was elevated in cells undergoing a change of direction relative to cells migrating persistently in one direction. Migrating cells contained gradients of [Ca2+]i along their long axis, with the front of the cell having consistently lower [Ca2+]i than the rear. When cells were loaded with the cell-permeant form of fura 2, fura 2 acetoxymethyl ester, a caffeine-sensitive membrane-delimited region of elevated [Ca2+]i was seen associated with the microtubule organizing center. A model is proposed relating the distribution of [Ca2+]i and the location of the external stimulus to the generation and interaction of substances within the cell that both simulate and inhibit increases in [Ca2+]i.
Am J Physiol. 1993 Dec;265(6 Pt 1):C1527-43.
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/32815