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γ‐Hydroxybutyric Acid Increases Intracellular Ca 2+ Concentration and Nuclear Cyclic AMP‐Responsive Element‐and Activator Protein 1 DNA‐Binding Activities Through GABA B Receptor in Cultured Cerebellar Granule Cells
Author(s) -
Ito Yoshihisa,
Ishige Kumiko,
Zaitsu Eiko,
Anzai Kaijiro,
Fukuda Hideomi
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.65010075.x
Subject(s) - activator (genetics) , cerebellum , granule cell , intracellular , microbiology and biotechnology , biochemistry , chemistry , receptor , biology , hippocampal formation , endocrinology , dentate gyrus
In primary cultures of mouse cerebellar granule cells, a brief stimulation by γ‐hydroxybutyric acid (GHB, 0.1–3 m M ) significantly increased the intracellular Ca 2+ concentration ([Ca 2+ ] i ) in a concentration‐dependent manner. In addition, gel mobility assay showed that exposure of the cells to GHB also increased nuclear DNA‐binding activity specific for the cyclic AMP‐responsive element (CRE) and activator protein 1 (AP‐1) transcriptional element in a concentration‐dependent manner. The concentration range of GHB that increased the DNA‐binding activity was essentially the same as the concentration range that elicited the increase in [Ca 2+ ] i . The GHB‐induced increases in [Ca 2+ ] i and nuclear DNA‐binding activity were antagonized by specific GABA B antagonists such as p ‐[3‐aminopropyl]‐ p ‐diethoxymethylphosphinic acid (CGP 35 348) and 3‐ N ‐[1‐( S )‐(3,4‐dichlorobenzyl)ethanol‐2‐( S )‐hydroxy‐ P ‐benzylphosphinic acid (CGP 55 845). In addition, the GHB‐induced increase in [Ca 2+ ] i was abolished by pretreatment of the cells with islet‐activating protein. Furthermore, treatment of the cells with 1,2‐bis(2′‐aminophenoxy)ethane‐ N,N,N′,N′ ‐tetraacetic acid tetraacetoxymethyl ester (BAPTA‐AM) and thapsigargin blocked the GHB‐induced increase in nuclear DNA‐binding activity. GHB inhibited [ 3 H]baclofen binding to cultured cerebellar granule cells and mouse cerebellar membranes. These results suggest that stimulation of GABA B receptors by GHB activates intracellular Ca 2+ stores and that the increased [Ca 2+ ] i resulting from release of stored Ca 2+ plays an important role in increasing the CRE‐ and AP‐1 DNA‐binding activities in cultured cerebellar granule cells.