ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Prolonged hypoxia exerts profound effects on cell function, and has been associated with increased production of amyloid β peptides (AβPs) of Alzheimer's disease. Here, we have investigated the effects of chronic hypoxia (2.5% O2, 24 h) on capacitative Ca2+ entry (CCE) in primary cultures of rat type-I cortical astrocytes, and compared results with those obtained in astrocytes exposed to AβPs. Chronic hypoxia caused a marked enhancement of CCE that was observed after intracellular Ca2+ stores were depleted by bradykinin application or by exposure to thapsigargin (1 µm). Exposure of cells for 24 h to 1 µm AβP(1−40) did not alter CCE. Enhancement of CCE was not attributable to cell hyperpolarization, as chronically hypoxic cells were significantly depolarized as compared with controls. Mitochondrial inhibition [by FCCP (10 µm) and oligomycin (2.5 µg/mL)] suppressed CCE in all three cell groups, but more importantly there were no significant differences in the magnitude of CCE in the three astrocyte groups under these conditions. Similarly, the antioxidants melatonin and Trolox abolished the enhancement of CCE in hypoxic cells. Our results indicate that chronic hypoxia augments CCE in cortical type-I astrocytes, a finding which is not mimicked by AβP(1−40) and appears to be dependent on altered mitochondrial function.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.2003.01785.x
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