Inhibition of NMDA receptors underlies the neuroprotective effect of ginsenoside Rb3.
In order to investigate the mechanisms underlying the neuroprotective effect of ginsenoside Rb3, rat hippocampal neurons were primarily cultured, and exposed to 1 mM N-methyl-D-aspartate (NMDA), cell viability and lactate dehydrogenase leakage were measured. Ca2+ influx was determined by calcium imaging with a laser confocal microscopy. The influences of ginsenoside Rb3 on these variables were examined. Patch-clamp technique was used to observe the effects of ginsenoside Rb3 on NMDA-evoked current. The results show that treatment of Rb3 raised the neuronal viability, reduced the leakage of lactate dehydrogenase, and inhibited NMDA-elicited Ca2+ influx in a dose-dependent manner. In the presence of Rb3, NMDA-evoked peak current was inhibited, and Ca2+-induced desensitization of NMDA current was facilitated. It is suggested that ginsenoside Rb3 could exert a neuroprotective role on hippocampal neurons, a role which was partly mediated by the facilitation of Ca2+-dependent deactivation of NMDA receptors, and the resultant reduction of intracellular free Ca2+ level.
Peng
Liang-Liang
LL
Department of Neuropharmacology, Institute of Nautical Medicine, Nantong University, Nantong, Jiangsu 226001, China.
Shen
Hong-Mei
HM
Jiang
Zheng-Lin
ZL
Li
Xia
X
Wang
Guo-Hua
GH
Zhang
Yun-Feng
YF
Ke
Kai-Fu
KF
D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D036145:Ginsenosides / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D018613:Microscopy, Confocal; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013997:Time Factors
D036145:Ginsenosides; D018696:Neuroprotective Agents; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; C044463:ginsenoside Rb3; D002118:Calcium