TY - JOUR
T1 - Glucocorticoids prolong CA2+ transients in hippocampal-derived h19-7 neurons by repressing the plasma membrane CA2+-atpase-1
AU - Bhargava, Aditi
AU - Mathias, Robert S.
AU - McCormick, James A.
AU - Dallman, Mary F.
AU - Pearce, David
PY - 2002
Y1 - 2002
N2 - Calcium ions (Ca2+) play an important role in mediating an array of structural and functional responses in cells. In hippocampal neurons, elevated glucocorticoid (GC) levels, as seen during stress, perturb calcium homeostasis and result in altered neuronal excitability and viability. Ligand- and volt-age-gated calcium channels have been the presumed targets of hormonal regulation; however, circumstantial evidence has suggested the possibility that calcium extrusion might be an important target of GC regulation. Here we demonstrate that GC-induced repression of the plasma membrane Ca2+-ATPase-1 (PMCA1) is an essential determinant of intracellular Ca2+ levels ([Ca2+]i) in cultured hippocampal H19-7 cells. In particular, GC treatment caused a prolongation of agonist-evoked elevation of [Ca2+]i that was prevented by the expression of exogenous PMCA1. Furthermore, selective inhibition of PMCA1 using the RNA interference technique caused prolongation of Ca2+ transients in the absence of GC treatment. Taken together, these observations suggest that GC-mediated repression of PMCA1 is both necessary and sufficient to increase agonist-evoked Ca2+ transients by down-regulating Ca2+ extrusion mechanisms in the absence of effects on calcium channels. Prolonged exposure to GCs, resulting in concomitant accumulation of [Ca2+]i, is likely to compromise neuronal function and viability.
AB - Calcium ions (Ca2+) play an important role in mediating an array of structural and functional responses in cells. In hippocampal neurons, elevated glucocorticoid (GC) levels, as seen during stress, perturb calcium homeostasis and result in altered neuronal excitability and viability. Ligand- and volt-age-gated calcium channels have been the presumed targets of hormonal regulation; however, circumstantial evidence has suggested the possibility that calcium extrusion might be an important target of GC regulation. Here we demonstrate that GC-induced repression of the plasma membrane Ca2+-ATPase-1 (PMCA1) is an essential determinant of intracellular Ca2+ levels ([Ca2+]i) in cultured hippocampal H19-7 cells. In particular, GC treatment caused a prolongation of agonist-evoked elevation of [Ca2+]i that was prevented by the expression of exogenous PMCA1. Furthermore, selective inhibition of PMCA1 using the RNA interference technique caused prolongation of Ca2+ transients in the absence of GC treatment. Taken together, these observations suggest that GC-mediated repression of PMCA1 is both necessary and sufficient to increase agonist-evoked Ca2+ transients by down-regulating Ca2+ extrusion mechanisms in the absence of effects on calcium channels. Prolonged exposure to GCs, resulting in concomitant accumulation of [Ca2+]i, is likely to compromise neuronal function and viability.
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U2 - 10.1210/mend.16.7.0861
DO - 10.1210/mend.16.7.0861
M3 - Article
C2 - 12089356
AN - SCOPUS:85047685474
SN - 0888-8809
VL - 16
SP - 1629
EP - 1637
JO - Molecular Endocrinology
JF - Molecular Endocrinology
IS - 7
ER -