In:
Canadian Journal of Physiology and Pharmacology, Canadian Science Publishing, Vol. 81, No. 6 ( 2003-06-01), p. 654-662
Kurzfassung:
The use of an ET-1 fluorescent probe in human heart and vascular smooth muscle cells showed that ET-1 receptors are present at both the sarcolemma and nuclear envelope membranes. The use of immunofluorescence studies showed that the ET A receptor was mainly present at the sarcolemma and cytosolic levels. However, the ET B receptor was present at the sarcolemma and the cytosol, as well as the nuclear envelope membranes and the nucleoplasm. In addition, ET-1 immunoreactivity was seen in the cytosol and the nucleus. Using Ca 2+ fluorescent probes such as Fluo-3, Indo 1, and yellow cameleon, as well as confocal microscopy three-dimensional image measurement technique, stimulation of ET-1 receptors at the sarcolemma membranes induced an increase of cytosolic and nuclear free Ca 2+ levels. This effect of extracellular ET-1 was blocked by removal of extracellular calcium. Direct stimulation of ET-1 receptors at the nuclear envelope membranes also induced an increase of intranuclear free Ca 2+ level. Our results suggest that the stimulation of sarcolemmal Ca 2+ influx by ET-1 seems to be due to the activation of ET A and ET B receptors. However, the increase of nucleoplasmic Ca 2+ levels by cytosolic ET-1 seems to be mediated via the activation of ET B receptors. Activation of nuclear membranes ET B receptors seems to prevent nuclear Ca 2+ overload and may protect the cell from apoptosis.Key words: endothelin-1, endothelin-1 receptors, calcium, nuclear receptors, confocal microscopy.
Materialart:
Online-Ressource
ISSN:
0008-4212
,
1205-7541
Sprache:
Englisch
Verlag:
Canadian Science Publishing
Publikationsdatum:
2003
ZDB Id:
2004356-9
