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Journal of Biomedicine and Biotechnology
Volume 2006 (2006), Article ID 97803, 7 pages
http://dx.doi.org/10.1155/JBB/2006/97803
Research Article

Neutrophil Secretion Induced by an Intracellular Ca2+ Rise and Followed by Whole-Cell Patch-Clamp Recordings Occurs Without any Selective Mobilization of Different Granule Populations

1The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Göteborg University, Guldhedsgatan 10, Göteborg 413 46, Sweden
2Department of Chemistry & Bioscience, Chalmers University of Technology, Kemivägen 10, Göteborg 412 96, Sweden
3Univa AB, Lunds Universitet, Lund 221 00, Sweden

Received 20 December 2005; Revised 22 March 2006; Accepted 4 May 2006

Copyright © 2006 Daniel Granfeldt et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We have investigated calcium-induced secretion in human neutrophils, using a whole-cell patch-clamp technique. Mobilization of subcellular granules to the cell membrane was followed as the change in membrane capacitance (Cm). Both the magnitude and the kinetics of the response differed between low and high concentrations of Ca2+. A sustained secretion following a short lag phase was induced by high concentrations of Ca2+ (100 μM and higher). A stable plateau was reached after 5–7 minutes at Cm values corresponding to values expected after all specific as well as azurophil granules have been mobilized. Capacitance values of the same magnitude could be obtained also at lower Ca2+ concentrations, but typically no stable plateau was reached within the measuring time. In contrast to previous studies, we were unable to detect any pattern of secretion corresponding to a distinct submaximal response or selective mobilization of granule subsets specified by their Ca2+-sensitivity.