[Show abstract][Hide abstract] ABSTRACT: The present study investigated the effect of schizandrin, a component of the fruit of Schizandra chinesis Baill (Fructus Schizandrae), on memory impairment in rats. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, markedly impaired spatial memory in an eight-arm radial maze. A higher dose of scopolamine (3 mg/kg, i.p.) also impaired the passive avoidance response. Schizandrin (1 and 10 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of spatial memory. Similarly, schizandrin (1 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of the passive avoidance response. Moreover, in mice, schizandrin (1 and 10 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M(1) receptor agonist. Taken together these findings suggest that schizandrin reverses scopolamine-induced memory impairment, in part, by enhancing cholinergic function, and that schizandrin might be useful for treating memory deficits.
Phytotherapy Research 02/2008; 22(1):49-52. · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study investigated the effects of Kamikihi-to (KKT), a Kampo medicine, on impairment of spatial memory in rats using an eight-arm radial maze task. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, and Delta(9)-tetrahydrocannabinol (THC; 6 mg/kg, i.p.), a principal psychoactive component of marihuana, each markedly impaired the spatial memory. KKT (1 and 3 mg/kg, p.o.) significantly improved the scopolamine-induced impairment of spatial memory. KKT (30 mg/kg, p.o.) also improved significantly the THC-induced impairment of spatial memory. Moreover, KKT (3 and 30 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M(1) receptor agonist. Taken together these findings suggest that KKT is a useful drug for treating memory deficits.
Phytotherapy Research 03/2007; 21(2):126-9. · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Amyloid beta protein (Abeta) is the major component of senile plaques, the pathological hallmark of the neurodegeneration associated with Alzheimer's disease (AD). This study investigated the effect of Toki-shakuyaku-san (TSS), a traditional medicine, on Abeta25-35-induced neuronal death and lipid peroxidation assessed by measuring lactate dehydrogenase (LDH) and malondialdehyde (MDA), respectively. Abeta25-35 at 10 microM induced neuronal damage and increased the LDH and MDA. TSS at concentrations of 100 and 300 microg/mL significantly reduced the Abeta25-35-induced neuronal death and the lipid peroxidation. These results suggest that TSS has a protective effect against Abeta25-35-induced neuronal damage. TSS may be beneficial for the treatment of AD.
Phytotherapy Research 06/2005; 19(5):450-3. · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previously we have reported that Toki-shakuyaku-san (TSS) ameliorated the impairment of spatial memory induced by single cerebral ischemia (1 x 10 minutes) and scopolamine, a muscarinic receptor antagonist. In this experiment, we studied the effect of TSS on repeated cerebral ischemia (2 x 10 minutes, 1-hour interval) induced impairment of spatial memory and neuronal injury in rats. The 8-day post-ischemic treatment with TSS (30-300 mg/kg) was administered p.o. once per day. TSS dose-dependently prevented the impairment of spatial memory, neuronal death and TUNEL positive cells induced by repeated cerebral ischemia. In order to determine the mechanism of TSS, we also studied the effect of TSS on GluR2 mRNA, one of the glutamate alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) receptor subunits. Repeated cerebral ischemia significantly decreased GluR2 flop mRNA at 1 and 3 days after the occlusion. TSS (300 mg/kg) significantly suppressed the decrease in GluR2 flop at 3 days after repeated cerebral ischemia. These results suggested that the TSS has neuroprotective action which may be indirectly mediated by the AMPA receptor, and TSS may be beneficial for the treatment of cerebrovascular dementia.
The American Journal of Chinese Medicine 02/2005; 33(3):475-89. · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The improving effects of various components of Toki-Shakuyaku-San (TSS) and fractions isolated from Angelica acutiloba Radix (Toki) on scopolamine-induced spatial memory impairment were investigated in eight-armed radial maze. The scopolamine-induced memory impairment was characterized by prominent increase of error choices in addition to decreased correct choices. Toki, Cnidium officinale Rhizoma (Senkyu), Poria cocos Hoelen (Bukuryo), Alisma orientale Rhizoma (Takusha), and Atractylodes lancea Rhizoma (Sojutsu) increased the correct choices, while only the Toki, Sojutsu, and Takusha decreased the error choices. No effect was produced by Paeonia lactiflora Radix (Shakuyaku). Investigation of effects of fractions isolated from Toki revealed that its activity mainly resided in the butanol layer and its contents of N-methyl-beta-carboline-3-carboxamide and amines. Moreover, the alkaloid, internal and external solutions (containing poly-, di-, and monosaccharides) obtained by dialysis with Visking cellophane tubing also improved the memory. However, no improving properties were detected for methanol and hexanol layers, L-(-)-tryptophan, L-arginine, L-(-)-lysine, and choline chloride. The results showed that the TSS components could improve the reference and working memory impaired by scopolamine. The improving effect of TSS is produced greatly by the Toki component, the activity of which was greatly produced by the fraction extracted by butanol.
Journal of Pharmacological Sciences 10/2004; 96(1):33-41. · 2.15 Impact Factor