TY - JOUR
T1 - Interference of heavy metal cations with fluorescent Ca2+ probes does not affect Ca2+ measurements in living cells
AU - Marchi, B.
AU - Burlando, B.
AU - Panfoli, I.
AU - Viarengo, A.
N1 - Funding Information:
This work was supported by the Italian Ministry for University and Scientific Research, and by the Italian National Program for Antarctic Research.
PY - 2000
Y1 - 2000
N2 - In studies about the effects of heavy metals on intracellular Ca2+, the use of fluorescent probes is debated, as metal cations are known to affect the probe signal. In this study, spectrofluorimetric experiments in free solution, using Fluo-3 and Fura-2, showed that Zn2+ and Cd2+ enhanced the probe signal, Cu2+ quenched it, and Hg2+ had no effect. Addition of GSH prevented most of these effects, suggesting the occurrence of a similar protective role in living cells. Digital imaging of living mussel haemocytes loaded with Fura-2/AM or Fluo-3/AM showed that Hg2+, Cu2+ and Cd2+ induced a rise in probe fluorescence, whereas up to 200 μM Zn2+ had no effect. In particular, Cd2+ produced the strongest probe signal rise in free solution, but the lowest fluorescence increase in cells. Probe calibration yielded [Ca2+](i) values characteristic of resting levels in control and Zn2+-exposed cells, and, as expected, indicated Ca2+ homeostasis impairment in cells exposed to Cd2+, Cu2+ and Hg2+. Our results show that Ca2+ probe responses to heavy metals in living cells are completely different from those obtained in free solution, indicating that fluorescent probes can be a suitable tool to record the effects of heavy metals on [Ca2+](i). (C) 2000 Harcourt Publishers Ltd.
AB - In studies about the effects of heavy metals on intracellular Ca2+, the use of fluorescent probes is debated, as metal cations are known to affect the probe signal. In this study, spectrofluorimetric experiments in free solution, using Fluo-3 and Fura-2, showed that Zn2+ and Cd2+ enhanced the probe signal, Cu2+ quenched it, and Hg2+ had no effect. Addition of GSH prevented most of these effects, suggesting the occurrence of a similar protective role in living cells. Digital imaging of living mussel haemocytes loaded with Fura-2/AM or Fluo-3/AM showed that Hg2+, Cu2+ and Cd2+ induced a rise in probe fluorescence, whereas up to 200 μM Zn2+ had no effect. In particular, Cd2+ produced the strongest probe signal rise in free solution, but the lowest fluorescence increase in cells. Probe calibration yielded [Ca2+](i) values characteristic of resting levels in control and Zn2+-exposed cells, and, as expected, indicated Ca2+ homeostasis impairment in cells exposed to Cd2+, Cu2+ and Hg2+. Our results show that Ca2+ probe responses to heavy metals in living cells are completely different from those obtained in free solution, indicating that fluorescent probes can be a suitable tool to record the effects of heavy metals on [Ca2+](i). (C) 2000 Harcourt Publishers Ltd.
UR - http://www.scopus.com/inward/record.url?scp=0033758916&partnerID=8YFLogxK
U2 - 10.1054/ceca.2000.0155
DO - 10.1054/ceca.2000.0155
M3 - Article
SN - 0143-4160
VL - 28
SP - 225
EP - 231
JO - Cell Calcium
JF - Cell Calcium
IS - 4
ER -