Effects of Ginkgo biloba extracts on NMDA-activated currents in acutely isolated hippocampal neurons of the rat.
Ginkgo biloba extracts (GBE) have long been used as a traditional herbal medicine for treating central nervous system diseases and peripheral vascular diseases, but the underlying mechanisms have yet to be elucidated. Furthermore, traditional GBE is in the form of microsomes and only dissolves in organic solvents; its clinical applications have been greatly limited. Therefore, in the present study, nanometer GBE (nGBE) was prepared utilizing supercritical anti-solvent (SAS) upon CO(2) -supercritical fluid extraction (CO(2) -SPF). Using whole-cell patch clamp techniques, the effects of different preparations of GBE on N-methyl-D-aspartate (NMDA)-activated currents (I(NMDA) ) from acutely isolated rat hippocampal neurons were investigated and the difference in protective potency between nGBE and mGBE evaluated. The results showed that the inward current activated by NMDA could be depressed by mGBE and nGBE. The inhibitory rates were 40% ± 17% and 64% ± 15%, and the half-inhibition concentrations (IC(50) ) were 0.0210 ± 0.0055 and 0.0262 ± 0.0038 mg/mL, respectively. In comparison, the modulatory effect of nGBE (dissolved in extracellular solution) on NMDA-activated current was significantly greater than that of mGBE (dissolved in DMSO) (p < 0.05). This indicated that the modulatory effects of GBE on NMDA-activated current may contribute to the neuroprotective effects of GBE and the modulatory effect of nGBE on NMDA-activated current was greater than that of mGBE.
Li
Shao
S
Department of Physiology, Dalian Medical University, Dalian, PR China. lishao89@hotmail.com
Luo
Jie
J
Wang
Xi
X
Guan
Bing-Cai
BC
Sun
Chang-Kai
CK
D000818:Animals; D020441:Ginkgo biloba / Q000737:chemistry*; D006624:Hippocampus / Q000187:drug effects*; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018696:Neuroprotective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D010316:Particle Size; D018408:Patch-Clamp Techniques; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology; D012995:Solubility
D018696:Neuroprotective Agents; D010936:Plant Extracts; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate