[Effects of coriaria lactone on the concentration of intracellular free calcium of rat hippocampal neurons].
We instituted an investigation to elucidate the role of Ca2+ and calcium channels in epileptogenesis and to analyze the mechanism by which coriaria lactone (CL) regulates intracellular Ca2+ concentration. The hippocampal neurons of Sprague-Dawley rats (post natal days 7 to 14) were acutely isolated and loaded with calcium-sensitive fluorescent indicator Fluo-3/AM. Intracellular calcium concentration ([Ca2+]i) changes were measured using laser scanning confocal microscopy. The study included five groups, namely the CL group, the NiCl2 plus CL group, the Nifedipine plus CL group, the NiCl2+ Nifedipine plus CL group, and the control group. The results indicated that 20 microl/ml CL induced a significant increase of [Ca2+]i in hippocampal neurons when compared to the control (P < 0.01), the mean fluorescent intensity of intracellular calcium displaying an increase from 5.46 +/- 2.37 to 34.03 +/- 3.45. Although the increase of relative intracellular fluorescent intensity was delayed by 3 or 4 minutes in the NiCl2 plus CL group, the Nifedipine plus CL group, and the NiCl2+ Nifedipine plus CL group, yet the use to 20 microl/ml CL in these 3 groups caused a significant ascending level of the fluorescent intensities (from 3.94 +/- 1.75 to 30.18 +/- 4.22; from 3.38 +/- 1.11 to 36.39 +/- 3.97; from 3.05 +/- 1.02 to 28.05 +/- 2.71), and the effect was comparable to that observed in the CL group (P > 0.05). So CL can increase [Ca2+]i in acutely isolated rat hippocampal neurons. This effect can be delayed but can not be completely blocked by NiCl2 and Nifedipine. These findings indicate that CL can increase [Ca2+]i by other means besides T- and L-type voltage-gated calcium channels, and that CL can increase the excitability of neurons and play a role in the epileptogenesis process.
Lai
Xiaohui
X
Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, China.
Zhang
Qin
Q
Zhou
Dong
D
D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism; D005260:Female; D006624:Hippocampus / Q000378:metabolism*; D007783:Lactones / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015220:Calcium Channels; D007783:Lactones; C049836:coriaria lactone; D002118:Calcium