Localization of chlorotetracycline fluorescence in human polymorphonuclear
neutrophils
TD Coates, M Torres, J Harman and V Williams
Chlorotetracycline (CTC) has been used in many cells as a probe for
membranous calcium. In polymorphonuclear neutrophils (PMN), the changes in
CTC fluorescence upon stimulation are considered to monitor an early event
in the activation process. Using quantitative video-enhanced microscopy, we
report that in resting cells about 80% of the CTC signal emanates from the
perinuclear region of the cell, indicating that internal structures are
labeled with CTC. Approximately 20% of the total CTC fluorescence is taken
up in a compartment sensitive to mitochondrial inhibitors, which is not
present in neutrophils depleted of nucleus and granules or cytoplasts. Upon
stimulation PMN loaded with CTC exhibit a rapid, biphasic decrease in
fluorescence that is dose dependent. The second phase of the response is
not seen in neutrophil cytoplasts. These results suggest that internal
stores of CTC are responsive upon stimulation and could account for the
later decrease in CTC fluorescence, whereas the early phase of CTC changes
represents the plasma membrane response.
Volume 69,
Issue 4,
pp. 1146-1152,
04/01/1987
Copyright © 1987 by The American Society of Hematology
