Exocytosis and intracellular free calcium ([Ca2+]in) were simultaneously recorded in single human neutrophils using patch-clamp capacitance measurements and the fura-2 fluorescence ratio method. Intracellular application of guanosine-5′-O(3-thiotriphosphate) (GTPγS) stimulates both exocytosis and a calcium transient. The calcium transient starts to develop after a lag phase of ∼40s and normally appears to trigger the onset of exocytosis indicated by the beginning of the capacitance increase. After this delay [Ca2+]in increases from ∼150 nM to ∼600 nM with a sigmoidal time course. The peak concentration is reached within ∼30 s but the main increase occurs during ∼ 3s. [Ca2+]in subsequently decays within 1–2 min to a level which is close to the resting value. This calcium transient is due to calcium release from inositoltrisphosphate-sensitive intracellular stores. Exocytosis also occurs if the calcium transient is abolished by intracellular EGTA but the lag phase is markedly prolonged. The GTPγS-induced calcium transient is very similar to that observed after stimulation with N-formyl-methionyl-leucyl-phenylalanine. The interplay between guanine nucleotides, [Ca2+]in and exocytosis in neutrophils closely resembles previous results obtained in mast cells suggesting a similar regulation of exocytosis in both cell types.
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February 01 1990
GTPγS-induced calcium transients and exocytosis in human neutrophils
Oliver Nüße;
Oliver Nüße
1Biophysics Group, Freie Universität Berlin, Arnimalle 14, D-1000 Berlin 33, FRG
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Manfred Lindau
Manfred Lindau
1Biophysics Group, Freie Universität Berlin, Arnimalle 14, D-1000 Berlin 33, FRG
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Publisher: Portland Press Ltd
Received:
September 12 1989
Online ISSN: 1573-4935
Print ISSN: 0144-8463
© 1990 Plenum Publishing Corporation
1990
Biosci Rep (1990) 10 (1): 93–103.
Article history
Received:
September 12 1989
Citation
Oliver Nüße, Manfred Lindau; GTPγS-induced calcium transients and exocytosis in human neutrophils. Biosci Rep 1 February 1990; 10 (1): 93–103. doi: https://doi.org/10.1007/BF01116857
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