Ca2+-dependent induction of intracellular Ca2+ oscillation in hippocampal astrocytes during metabotropic glutamate receptor activation.
We have investigated whether the intracellular calcium concentration ([Ca(2+)](i)) oscillations induced in astrocytes using the metabotropic glutamate-receptor agonist, (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) are Ca(2+)-dependent, using three different Ca(2+) indicators with different affinities for Ca(2+). When rat hippocampal cells in culture were loaded with fura-2 (K(d): 145 nM), two-thirds of the cells showed obvious oscillatory increase in [Ca (2+)](i) during t-ACPD-administration. Those cells were identified as astrocytes by immuno-histochemistry in our previous paper. In cells loaded with fura-2FF (K(d): 25,000 nM), a similar percentage of t-ACPD-responsive cells showed oscillatory [Ca(2+)](i) changes. However, in cells loaded with quin-2 (K(d): 60 nM), t-ACPD induced no oscillatory responses, but some cells showed a small transient increase in the [Ca(2+)](i). The same small transient [Ca(2+)](i) increase was seen in cells loaded with both fura-2FF and BAPTA, a Ca(2+) chelator (K(d): 135 nM). These findings indicate the involvement of [Ca(2+)](i)-dependent regulatory mechanisms in the induction of the t-ACPD-induced oscillatory change in the [Ca(2+)](i) in astrocytes.
Yoshida
Yoshitoku
Y
Molecular Life Science Division, School of Life Science, Tokyo University of Pharmacy and Life Science, Japan.
Tsuchiya
Remi
R
Matsumoto
Nagisa
N
Morita
Mitsuhiro
M
Miyakawa
Hiroyoshi
H
Kudo
Yoshihisa
Y
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D002118:Calcium / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D007424:Intracellular Fluid / Q000378:metabolism* / Q000502:physiology; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000378:metabolism*
D018094:Receptors, Metabotropic Glutamate; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D002118:Calcium