Coriaria Lactone Increased the Intracellular Level of Calcium through the Voltage-gated Calcium Channels in Rat Hippocampal Neurons
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To investigate the effects of Coriaria Lactone (CL), an epileptogenic substance, on intracellular levels of calcium ([Ca2+]i) and physiological properties of voltage-gated calcium channels (VGCCs). Ratiometric calcium imaging using Fura Red and whole-cell voltage patch-clamp technique were explored on freshly isolated rat hippocampal neurons exposed to CL. Coriaria Lactone increased [Ca2+]i from 118 ± 21 to 440 ± 35 nM; VGCCs and calcium influx through NMDA receptor served as the main routes of entry. Coriaria Lactone could enhance both Low voltage activated (LVA) and High voltage activated calcium currents in a concentration-dependent way, and its effect on LVA current was more potent (about 60%). The increased calcium currents were accompanied by the shift of voltage-dependent steady-state inactivation to more positive potentials. These effects of CL, especially its impact on LVA current, could activate different calcium-dependent signaling pathways, and influence cellular excitable properties as well, which might play an important role in CL’s epileptogenic process.
KeywordsCoriaria Lactone Calcium Voltage-gated calcium channel Hippocampal neurons Epilepsy
The authors would like to thank Dr. Zhenwei Liu and Dr. Christian Lohr for their kind help and critical suggestions during this research effort, and Mr. Shenghua Su, Mr. Chaoliang Zhang, Mr. Qian Hu and Mr. Xuelin Zhao, Dr. Zhiping Yao for technical assistance.
- 1.Okuda T, Yoshida T (1967) The correlation of coriamyrtin and tutin, and their absolute configurations. Chem Pharm Bull (Tokyo) 15:1955–1965Google Scholar
- 8.Stefan R, Heinz B (2006) Molecular and cellular mechanisms of pharmaco-resistance in epilepsy. Brain 129:18–35Google Scholar
- 10.Yang Y, Wu LS, Wu MH et al (2005) The effect of Coriaria Lactone on the transient outward potassium currents of rats. J Luzhou Med Coll 28:402–405 (Article in Chinese)Google Scholar
- 17.Zou XY, Zeng H, Zheng HB et al (2002) Effect of Coriaria Lactone on calcium homeostasis in pyramidal neurons of hippocampus of rats. Hua Xi Yi Ke Da Xue Xue Bao 33:379–380 (Article in Chinese)Google Scholar
- 18.Liao SJ, Zhou D (2003) Effect of the extracts of Szechwan Lovge Rhizome on [Ca2+]i of the cultured cortex neurons exposed to Coriaria Lactone. W China J Pharm Sci 18:84–87 (Article in Chinese)Google Scholar
- 25.Wang Q, Long J, Zhang ZQ et al (1999) Determination of glutamate, aspartate, glycine and γ-aminobutyric acid in cerebral cortex and hippocampus of epileptic rats induced by Coriaria Lactone. J Brain Nerv Dis 7:335–338 (Article in Chinese)Google Scholar
- 26.Wang Q, Ruan XZ, Shi TH (2000) The alterations of NMDA receptor subunit 1 mRNA in cerebral cortex and hippocampus of epileptic rats induced by Coriaria Lactone. J Apoplexy Nerv Dis 17:17–19 (Article in Chinese)Google Scholar
- 38.Yu DJ, Liu YH, Zhou JP (1996) The influence of Coriaria Lactone on the GABA and glutamate from the cultured hippocampal neuron. J Chin Histochem Cytochem 5:193–197 (Article in Chinese)Google Scholar