Liuwei Dihuang decoction facilitates the induction of long-term potentiation (LTP) in senescence accelerated mouse/prone 8 (SAMP8) hippocampal slices by inhibiting voltage-dependent calcium channels (VDCCs) and promoting N-methyl-d-aspartate receptor (NMDA) receptors

Abstract

Ethnopharmacological relevanceLiuwei Dihuang decoction (LW) is a typical traditional Chinese medicine (TCM) prescription and consists of six herbs including Rehmannia glutinosa Libosch. (family: Scrophulariaceae), Cornus officinalis Sieb. (family: Cornaceae), Dioscorea opposite Thunb. (family: Dioscoreaceae), Alisma orientale (G. Samuelsson) Juz (family: Alismataceae), Poria cocos (Schw.)Wolf (family: Polyporaceae) and Paeonia suffruticosa Andrews (family: Paeoniaceae). It has long been used clinically in treatment of many kinds of diseases with the sign of Yin insufficiency of kidney. Aim of the studyOur previous pharmacological studies demonstrated that LW possesses effect of ameliorating the decline of the learning and memory in senescence accelerated mouse/prone 8 (SAMP8), but the mechanism has not been well established. LW-containing serum (LWCS) is used in the current study to elucidate the possible mechanisms. Materials and methods6-month-old SAMP8 was used in this study to investigate the effect of LWCS on the induction of long-term potentiation (LTP). Primary cultured hippocampal neurons were used in this study to investigate the effects of LWCS on [Ca2+]i, ICa and N-Methyl-d-aspartate (NMDA)-evoked currents. [Ca2+]i was imaged using Fluo-3 and whole-cell patch recordings were applied to study the ICa and NMDA-evoked currents. ResultsWe find that LWCS facilitates the induction of LTP in hippocampal slices of 6-month-old SAMP8. In primary cultured hippocampal neurons, LWCS increases intracellular [Ca2+]i, the ICa is suppressed by LWCS, and NMDA-evoked currents are promoted. ConclusionThese results indicate that LW improves the synaptic plasticity by inhibiting voltage-dependent calciumchannels (VDCCs) and promoting the function of NMDA receptors. This improvement might be one of the mechanisms contributing to cognitive improvement effect of LW.