title: Chemotaxis of newt eosinophils: calcium regulation of chemotactic response.
abstract: Local 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.
authors.affiliation: Department of Physiology, University of Massachusetts Medical School, Worcester 01605.
authors.forename: R A
authors.initials: RA
authors.lastname: Brundage
authors.forename: K E
authors.initials: KE
authors.lastname: Fogarty
authors.forename: R A
authors.initials: RA
authors.lastname: Tuft
authors.forename: F S
authors.initials: FS
authors.lastname: Fay
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000097:blood*; D002631:Chemotactic Factors, Eosinophil / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000502:physiology*; D002850:Chromatography, Gel; D003035:Cobalt / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004804:Eosinophils / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D009355:Neomycin / Q000494:pharmacology; D012455:Salamandridae; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002631:Chemotactic Factors, Eosinophil; D005456:Fluorescent Dyes; C049925:fura-2-am; D003035:Cobalt; D002110:Caffeine; D004533:Egtazic Acid; D015759:Ionomycin; D014700:Verapamil; D009355:Neomycin; D002118:Calcium; D016257:Fura-2