Basic Mechanism Leading to Stimulation of Glycogenolysis by Isoproterenol, EGF, Elevated Extracellular K+ Concentrations, or GABA
Basic Mechanism Leading to Stimulation of Glycogenolysis by Isoproterenol, EGF, Elevated Extracellular K+ Concentrations, or GABA
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异丙肾上腺素、EGF、升高的细胞外钾浓度或 GABA 刺激糖原分解的基本机制
DOI：
10.1007/s11064-014-1244-z
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发表时间：
2014-02
影响因子：
4.4
通讯作者：
Peng, Liang
中科院分区：
文献类型：
--
作者：
Bai, Qiufang;Cai, Liping;Hertz, Leif;Peng, Liang
Glycogenolysis, in brain parenchyma an astrocyte-specific process, has changed from being envisaged as an emergency procedure to playing central roles during brain response to whisker stimulation, memory formation, astrocytic K+ uptake and stimulated release of ATP. It is activated by several transmitters and by even very small increases in extracellular K+ concentration, and to be critically dependent upon an increase in free cytosolic Ca2+ concentration ([Ca2+]i), whereas cAMP plays only a facilitatory role together with increased [Ca2+]i. Detailed knowledge about the signaling pathways eliciting glycogenolysis is therefore of interest and was investigated in the present study in well differentiated cultures of mouse astrocytes. The β-adrenergic agonist isoproterenol stimulated glycogenolysis by a β1-adrenergic effect, which initiated a pathway in which cAMP/protein kinase A activated a Gi/Gs shift, leading to Ca2+-activated glycogenolysis. Inhibition of this pathway downstream of cAMP but upstream of the Gi/Gs shift abolished the glycogenolysis. However, inhibitors operating downstream of the Ca2+-sensitive step, but preventing transactivation-mediated epidermal growth factor (EGF) receptor stimulation, a later step in the activated pathway, also caused inhibition of glycogenolysis. For this reason the effect of EGF was investigated and it was found to be glycogenolytic. Large increases in extracellular K+ activated glycogenolysis by a nifedipine-inhibited L-channel opening allowing influx of Ca2+, known to be glycogenolysis-dependent. Small increases (addition of 5 mM KCl) caused a smaller effect by a similarly glycogenolysis-reliant opening of an IP3 receptor-dependent ouabain signaling pathway. The same pathway could be activated by GABA (also in brain slices) due to its depolarizing effect in astrocytes.
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影响因子：
16.2
作者：
Choi HB;Gordon GR;Zhou N;Tai C;Rungta RL;Martinez J;Milner TA;Ryu JK;McLarnon JG;Tresguerres M;Levin LR;Buck J;MacVicar BA
通讯作者：
MacVicar BA
影响因子：
4.4
作者：
Lange SC;Bak LK;Waagepetersen HS;Schousboe A;Norenberg MD
通讯作者：
Norenberg MD
影响因子：
--
作者：
L. Hertz
通讯作者：
L. Hertz
DOI：
10.1007/978-3-319-08894-5_3
发表时间：
2014-01-01
期刊：
GLUTAMATE AND ATP AT THE INTERFACE OF METABOLISM AND SIGNALING IN THE BRAIN
影响因子：
--
作者：
Hertz, Leif;Xu, Junnan;Peng, Liang
通讯作者：
Peng, Liang
星形胶质细胞中糖原分解对吸收增加的细胞外 K 的要求：对脑中 K 稳态和糖原使用的潜在影响
影响因子：
4.4
作者：
Xu, Junnan;Song, Dan;Peng, Liang
通讯作者：
Peng, Liang