ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The effects of nitric oxide (NO)-generating agents on 45Ca2+ uptake in rat brain slices and cultured rat astrocytes were studied in the presence of monensin, which is considered to drive the Na+-Ca2+ exchanger in the reverse mode. Sodium nitroprusside (SNP) at 〉10 µM increased monensin-stimulated Ca2+ uptake in the slices, although it did not affect high K+-stimulated Ca2+ uptake. Another NO donor, 3-morpholinosydnonimine, was effective. The effect of SNP was antagonized by hemoglobin (50 µM), a NO scavenger, and mimicked by 8-bromo-cyclic GMP (100 µM). In rat brain synaptosomes, SNP increased monensin-stimulated Ca2+ uptake, but it did not affect high K+-stimulated Ca2+ uptake. 8-Bromocyclic GMP, but not SNP, increased Na+-dependent Ca2+ uptake significantly in synaptic membrane vesicles in the absence of monensin. In cultured rat astrocytes, SNP and 8-bromo-cyclic GMP increased Ca2+ uptake in the presence of ouabain and monensin, which were required for the Ca2+ uptake in the cells. These findings suggest that NO stimulates the Na+-Ca2+ exchanger in neuronal preparations and astrocytes in a cyclic GMP-dependent mechanism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.1995.64062437.x
