The novel psychoactive substance 25E-NBOMe induces reward-related behaviors via dopamine D1 receptor signaling in male rodents.

Novel psychoactive substances (NPSs) are new psychotropic drugs designed to evade substance regulatory policies. 25E-NBOMe (2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine) has recently been identified as an NPS, and its recreational misuse has been reported to be rapidly increasing. However, the psychopharmacological effects and mechanisms of 25E-NBOMe have not been studied. We examined the abuse potential of 25E-NBOMe using the conditioned place preference in male mice and self-administration paradigms in male rats. Additionally, immunoblot assay, enzyme-linked immunosorbent assay, and microdialysis were used to determine the molecular effects of 25E-NBOMe in the nucleus accumbens (NAc). Our data demonstrated that 25E-NBOMe induces conditioned place preference, and the dopaminergic signaling in the NAc mediates these. Following 25E-NBOMe administration, expression of dopamine transporter and dopamine D1 receptor (D1DR) were enhanced in the NAc of male mice, and NAc dopamine levels were reduced in both male mice and rats. Induction of intracellular dopaminergic pathways, DARPP32, and phosphorylation of CREB in the NAc of male mice was also observed. Significantly, pharmacological blockade of D1DR or chemogenetic inhibition of D1DR-expressing medium spiny neurons in the NAc attenuated 25E-NBOMe-induced conditioned place preference in male mice. We also examined the hallucinogenic properties of 25E-NBOMe using the head twitch response test in male mice and found that this behavior was mediated by serotonin 2A receptor activity. Our findings demonstrate that D1DR signaling may govern the addictive potential of 25E-NBOMe. Moreover, our study provides new insights into the potential mechanisms of substance use disorder and the improvement of controlled substance management.

Korean Red Ginseng inhibits methamphetamine addictive behaviors by regulating dopaminergic and NMDAergic system in rodents.

BACKGROUND: Methamphetamine (METH) is the most widely used psychostimulant and has been known to exhibit reinforcing effects even after long abstinence. We showed the inhibitory effect of Korean Red Ginseng extract (RGE) on METH-induced addictive behaviors in animal models mimicking the human drug-use pattern. METHODS: We first investigated the effect of RGE on the acquisition of METH-induced dependence using self-administration and conditioned place preference (CPP) tests. Additionally, further experiments such as METH-induced motivational behavior and seeking behavior were conducted. To study the underlying mechanism, dopamine receptor, dopamine transporter, and N-methyl-D-aspartate receptor were assessed through Western blot analysis. RESULTS: Treatment with RGE significantly reduced METH-induced self-administration on a fixed-ratio 1 schedule of reinforcement. It could be also decreased a progressive ratio schedule, and inhibited METH-primed reinstatement. In CPP, RGE significantly prevented the development of METH-induced CPP. Moreover, RGE not only shortened the withdrawal period clearly, but also prevented the reinstatement of CPP. RGE treatment also reversed METH-induced overexpression of dopamine transporter, dopamine receptor D1, and NMDA receptor in the nucleus accumbens. CONCLUSION: Our findings reflect that RGE has therapeutic potential to suppress METH-induced addictive behaviors by regulating dopaminergic and NMDAergic system.

Methoxphenidine (MXP) induced abnormalities: Addictive and schizophrenia-related behaviours based on an imbalance of neurochemicals in the brain.

BACKGROUND AND PURPOSE: Methoxphenidine is a dissociative-based novel psychoactive designer drug. Although fatal accidents from methoxphenidine abuse have been reported, recreational use of the drug continues. We aim to provide scientific supportfor legal regulation of recreational abuse of methoxphenidine by demonstrating its the pharmacological action. EXPERIMENTAL APPROACH: Addictive potential of methoxphenidine was examined using intravenous self-administration test with rats and conditioned place preference test with mice. Further, a series of behavioural tests (open field test, elevated plus maze test, novel object recognition test, social interaction test and tail suspension test) performed to assess whether methoxphenidine caused schizophrenia-related symptoms in mice. Additionally, neurotransmitter enzyme-linked immunosorbent assay and western blot were used to confirm methoxphenidine-induced neurochemical changes in specific brain regions related to abnormal behaviours. KEY RESULTS: Methoxphenidine caused addictive behaviours via reinforcing and rewarding effects. Consistently, methoxphenidine induced over-activation of dopamine pathways in the nuclear accumbens, indicating activation of the brain reward circuit. Also, methoxphenidine caused all categories of schizophrenia-related symptoms, including positive symptoms (hyperactivity, impulsivity), negative symptoms (anxiety, social withdrawal, depression) and cognitive impairment. Consistently, methoxphenidine led to the disruption of the hippocampal-prefrontal cortex pathway that is considered to be pathological involved in schizophrenia. CONCLUSIONS AND IMPLICATIONS: We demonastrate that methoxphenidine causes addictive and schizophrenia-like behaviours and induces neurochemical changes in brain regions associated with these behaviours. We propose that methoxphenidine could be used in developing useful animal disease models and that it also requires legal restrictions on its recreational use.

Abuse Potential of Synthetic Cannabinoids: AM-1248, CB-13, and PB-22.

Currently, the expanding recreational use of synthetic cannabinoids (SCBs) threatens public health. SCBs produce psychoactive effects similar to those of tetrahydrocannabinol, the main component of cannabis, and additionally induce unexpected pharmacological side effects. SCBs are falsely advertised as legal and safe, but in reality, SCB abuse has been reported to cause acute intoxication and addictive disorders. However, because of the lack of scientific evidence to elucidate their dangerous pharmacological effects, SCBs are weakly regulated and continue to circulate in illegal drug markets. In the present study, the intravenous self-administration (IVSA) paradigm was used to evaluate the abuse potential of three SCBs (AM-1248, CB-13, and PB-22) in rats. All three SCBs maintained IVSA with a large number of infusions and active lever presses, demonstrating their reinforcing effects. The increase of active lever presses was particularly significant during the early IVSA sessions, indicating the reinforcementenhancing effects of the SCBs (AM-1248 and CB-13). The number of inactive lever presses was significantly higher in the SCB groups (AM-1248 and CB-13) than that in the vehicle group, indicating their impulsive effects. In summary, these results demonstrated that SCBs have distinct pharmacological properties and abuse potential.

Korean Red Ginseng reduces chronic social defeat stress-induced mood disorders via N-methyl-D-aspartate receptor modulation in mice.

BACKGROUND: A chronic social defeat stress (CSDS) model has been proposed as relevant to stress-induced behavioral change in humans. In this study, we examined the effect of Korean Red Ginseng (KRG) on CSDS-induced mood disorders and protein expression in an animal model. METHODS: To evaluate the effect of KRG on social defeat stress, test mice were exposed in the resident aggressor's home cage compartment for 14 days beginning 1 h after KRG treatment (10, 20, and 40 mg/kg, per oral (p.o.)). After the exposure, behavioral tests to measure anxiety, social interaction, and depression-like behavior were performed. To investigate the underlying mechanism, N-methyl-D-aspartate receptor expression levels in CSDS-induced mice were evaluated using Western blot analysis. RESULTS: CSDS induced anxiety-like behaviors by decreasing central activity in the open-field test and open-arm approach in the elevated plus maze test and led to social avoidance behavior in the social interaction test. CSDS mice showed upregulated NR1, NR2A, and NR2B expression in the hippocampus. KRG 20 and 40 mg/kg ameliorated anxiety-like activities and KRG 20 mg/kg alleviated social avoidance by decreasing time in the corner zone. KRG treatment recovered CSDS-induced NR1, NR2A, and NR2B protein levels in the hippocampus. CONCLUSION: These results indicate that KRG has a therapeutic effect on CSDS-induced mood disorder by alleviating N-methyl-D-aspartate receptor overexpression in the hippocampus.

New designer phenethylamines 2C-C and 2C-P have abuse potential and induce neurotoxicity in rodents.

2C (2C-x) is the general name for the family of phenethylamines containing two methoxy groups at the 2 and 5 positions of the benzene ring. The abuse of 2C family drugs has grown rapidly, although the abuse potential and neurotoxic properties of 2C drugs have not yet been fully investigated. In this study, we investigated the abuse potential and neurotoxicity of 4-chloro-2,5-dimethoxyphenethylamine (2C-C) and 2,5-dimethoxy-4-propylphenethylamine (2C-P). We found that 2C-C and 2C-P produced conditioned place preference in a dose-dependent manner in mice, and increased self-administration in rats, suggesting that 2C-C and 2C-P have abuse potential. To investigate the neurotoxicity of 2C-C and 2C-P, we examined motor performance and memory impairment after high doses of 2C-C and 2C-P. High doses of 2C-C and 2C-P decreased locomotor activity, rota-rod performance, and lower Y-maze test, novel objective recognition test, and passive avoidance test scores. We also observed that 2C-C and 2C-P affected expression levels of the D1 dopamine receptor, D2 dopamine receptor, dopamine transporter, and phospho-dopamine transporter in the nucleus accumbens and the medial prefrontal cortex, and increased c-Fos immuno-positive cells in the nucleus accumbens. Moreover, high doses of 2C-C and 2C-P induced microglial activation, which is involved in the inflammatory reaction in the striatum. These results suggest that 2C-C and 2C-P have abuse potential by affecting dopaminergic signaling and induce neurotoxicity via initiating neuroinflammation at high doses.

Antineuroinflammatory Effects of 7,3',4'-Trihydroxyisoflavone in Lipopolysaccharide-Stimulated BV2 Microglial Cells through MAPK and NF-κB Signaling Suppression.

Neuroinflammation-a common pathological feature of neurodegenerative disorders such as Alzheimer's disease-is mediated by microglial activation. Thus, inhibiting microglial activation is vital for treating various neurological disorders. 7,3',4'-Trihydroxyisoflavone (THIF)-a secondary metabolite of the soybean compound daidzein-possesses antioxidant and anticancer properties. However, the effects of 7,3',4'-THIF on microglial activation have not been explored. In this study, antineuroinflammatory effects of 7,3',4'-THIF in lipopolysaccharide (LPS)-stimulated BV2 microglial cells were examined. 7,3',4'-THIF significantly suppressed the production of the proinflammatory mediators nitric oxide (NO), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) as well as of the proinflammatory cytokine interleukin-6 (IL-6) in LPS-stimulated BV2 microglial cells. Moreover, 7,3',4'-THIF markedly inhibited reactive oxygen species (ROS) generation. Western blotting revealed that 7,3',4'-THIF diminished LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), glycogen synthase kinase-3ß (GSK-3ß), and nuclear factor kappa B (NF-κB). Overall, 7,3',4'-THIF exerts antineuroinflammatory effects against LPS-induced microglial activation by suppressing mitogen-activated protein kinase (MAPK) and NF-κB signaling, ultimately reducing proinflammatory responses. Therefore, these antineuroinflammatory effects of 7,3',4'-THIF suggest its potential as a therapeutic agent for neurodegenerative disorders.

Flavonoids as therapeutic candidates for emotional disorders such as anxiety and depression.

Emotional disorders such as anxiety and depression are widespread psychological diseases that affect up to 20% of the world's population. There are many approaches to the discovery of novel agents for the treatment of depressive- and anxiety-like symptoms. However, the efficacy of existing drugs for emotional disorders is only exerted after a few weeks of treatment and have serious side effects. Due to this, new strategies to find suitable and safe options are being sought by many researchers. Among them, a lot of interest has been attracted by plant-derived natural compounds due to their wide range of beneficial effects for new agent development. Flavonoids are natural polyphenol-like compounds found commonly in plants, fruits, vegetables, and medicinal herbs. A diverse range of flavonoids have been studied to investigate their potential therapeutic activities for the treatment of brain-associated disorders, including anxiety and depression. The main aim of this review is to understand the associations between the various flavonoids and the emotional disorders and discuss the therapeutic effects of these natural compounds that were demonstrated during the conduction of recent studies. The current work shows advances in the latest research of some flavonoids as a potential candidate for the treatment of emotional disorders. We summarize their behavioral, molecular, physiological, and neurochemical effects in various in vitro and in vivo models. Therefore, in the present work, the latest studies were collected on the most important flavonoid compounds and their underlying mechanisms of action in emotion-related disorders were discussed.

25C-NBF, a new psychoactive substance, has addictive and neurotoxic potential in rodents.

The use of new psychoactive substances (NPSs) as a substitute for illegal drugs is increasing rapidly and is a serious threat to public health. 25C-NBF is a newly synthesized phenethylamine-type NPS that acts as a 5-hydroxyindoleacetic acid (5-HT) receptor agonist, but little is known about its pharmacological effects. Considering that NPSs have caused unexpected harmful effects leading to emergency and even death, scientific confirmation of the potential adverse effects of 25C-NBF is essential. In the present study, we investigated whether 25C-NBF has addictive and neurotoxic potential and causes neurochemical changes. In addictive potential assessments, high conditioned place preference (CPP) scores and stable self-administration (SA) were observed in the 25C-NBF groups (CPP [3 mg kg-1]; SA [0.01, 0.03, 0.1 mg kg-1]), suggesting the addictive liability of 25C-NBF. In neurotoxic potential assessments, 25C-NBF treatment (single super-high dose [1 × 15, 30, 40 mg kg-1]; repeated high dose [4 × 8, 15, 30 mg kg-1]) resulted in reduced motor activity (open field test), abnormal motor coordination (rota-rod test) and impaired recognition memory (novel object recognition test), suggesting that 25C-NBF is neurotoxic leading to motor impairment and memory deficits. Subsequently, immunohistochemistry showed that 25C-NBF treatment decreased tyrosine hydroxylase (TH) expression and increased ionized calcium-binding adapter molecule 1 (Iba-1) expression in the striatum. Taken together, our results clearly demonstrate the dangers of recreational use of 25C-NBF, and we suggest that people stop using 25C-NBF and other NPSs whose pharmacological effects are not precisely known.

Memory-enhancing effects of 7,3',4'-trihydroxyisoflavone by regulation of cholinergic function and BDNF signaling pathway in mice.

7,3',4'-Trihydroxyisoflavone (THIF) is a secondary metabolite derived from daidzein and is abundantly present in soybeans. Daidzein and 7,3',4'-THIF exhibit several pharmacological activities, including antioxidant and anti-atopic properties. However, the effects of 7,3',4'-THIF on cognitive function have not been fully investigated. Here, we evaluated the effects of 7,3',4'-THIF on memory using Y-maze and passive avoidance tests. The positive control groups were given donepezil (5 mg/kg, p.o.) or piracetam (200 mg/kg, i.p.) and the treated groups were given 7,3',4'-THIF (0.25, 0.5 and 1 mg/kg, p.o.). 7,3',4'-THIF at 1 mg/kg and donepezil at 5 mg/kg effectively ameliorated memory impairments induced by scopolamine (0.5 mg/kg, i.p.) in mice. In addition, 7,3',4'-THIF at 1 mg/kg and piracetam at 200 mg/kg significantly enhanced memory in intact mice. To examine the underlying mechanisms of 7,3',4'-THIF on cognition following behavioral experiments, biochemical tests were performed in the whole hippocampus. 7,3',4'-THIF (1 mg/kg, p.o.) significantly recovered scopolamine-induced cholinergic impairments. Moreover, brain-derived neurotrophic factor (BDNF), postsynaptic density protein-95 (PSD-95), and synaptophysin, along with phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and cAMP response element binding (CREB), were significantly increased by 7,3',4'-THIF (1 mg/kg, p.o.). Our findings indicate that 7,3',4'-THIF improves cognitive function by regulating cholinergic system and BDNF signaling.

Protective effects of 6,7,4'-trihydroxyisoflavone, a major metabolite of daidzein, on 6-hydroxydopamine-induced neuronal cell death in SH-SY5Y human neuroblastoma cells.

Daidzein, one of the important isoflavones, is extensively metabolized in the human body following consumption. In particular, 6,7,4'-trihydroxyisoflavone (THIF), a major metabolite of daidzein, has been the focus of recent investigations due to its various health benefits, such as anti-cancer and anti-obesity effects. However, the protective effects of 6,7,4'-THIF have not yet been studied in models of Parkinson's disease (PD). Therefore, the present study aimed to investigate the protective activity of 6,7,4'-THIF on 6-hydroxydopamine (OHDA)-induced neurotoxicity in SH-SY5Y human neuroblastoma cells. Pretreatment of SH-SY5Y cells with 6,7,4'-THIF significantly inhibited 6-OHDA-induced neuronal cell death, lactate dehydrogenase release, and reactive oxygen species production. In addition, 6,7,4'-THIF significantly attenuated reductions in 6-OHDA-induced superoxide dismutase activity and glutathione content. Moreover, 6,7,4'-THIF attenuated alterations in Bax and Bcl-2 expression and caspase-3 activity in 6-OHDA-induced SH-SY5Y cells. Furthermore, 6,7,4'-THIF significantly reduced 6-OHDA-induced phosphorylation of c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, and extracellular signal-regulated kinase 1/2. Additionally, 6,7,4'-THIF effectively prevented 6-OHDA-induced loss of tyrosine hydroxylase. Taken together, these results suggest that 6,7,4'-THIF, a major metabolite of daidzein, may be an attractive option for treating and/or preventing neurodegenerative disorders such as PD.

Lespedeza bicolor Extract Improves Amyloid Beta25 - 35-Induced Memory Impairments by Upregulating BDNF and Activating Akt, ERK, and CREB Signaling in Mice.

Lespedeza bicolor, a traditional herbal medicine widely used in Australia, North America, and Eastern Asia, has various therapeutic effects on inflammation, nephritis, hyperpigmentation, and diuresis. In this study, to evaluate the effects of L. bicolor on cognitive function, we examined whether L. bicolor improved amyloid beta-induced memory impairment and assessed the possible mechanisms in mice. Catechin, rutin, daidzein, luteolin, naringenin, and genistein were identified in the powdered extract of L. bicolor by HPCL-DAD analyses. In behavioral experiments, L. bicolor (25 and 50 mg/kg, p. o.) significantly improved amyloid beta25 - 35 (6 nmol, intracerebroventricular)-induced cognitive dysfunction in the Y-maze, novel recognition, and passive avoidance tests. Our molecular studies showed L. bicolor (25 and 50 mg/kg, p. o.) significantly recovered the reduced glutathione content as well as increased thiobarbituric acid reactive substance and acetylcholinesterase activities in the hippocampus. Furthermore, we found that L. bicolor significantly increased the expression of brain-derived neurotrophic factor, and phospho-Akt, extracellular signal-regulated kinase, and cAMP response element binding caused by amyloid beta25 - 35 in the hippocampus. In conclusion, L. bicolor exerts a potent memory-enhancing effect on cognitive dysfunction induced by amyloid beta25 - 35 in mice.

A novel designer drug, 25N-NBOMe, exhibits abuse potential via the dopaminergic system in rodents.

New psychoactive substances that have been modified and developed to mimic the effects of already prohibited drugs are an increasingly global problem. Among them, 2-(2,5-dimethoxy-4-nitrophenyl)-N-(2-methoxybenzyl)ethanamine (25 N-NBOMe) belonging to the N-methoxybenzyl-phenethylamines (NBOMes) class has recently emerged as a new psychoactive substance. However, the rewarding effects of 25 N-NBOMe have not yet been studied. Here, we investigated the addictive potential of 25 N-NBOMe using conditioned place preference and self-administration in rodents. We also evaluated the effects of 25 N-NBOMe on the dopaminergic system using Western blot analysis. We found that 25 N-NBOMe at 3 mg/kg significantly increased conditioned place preference in mice and 25 N-NBOMe at 0.01 mg/kg/infusion significantly enhanced self-administration in rats. In addition, repeated administration of 25 N-NBOMe did not affect the expression of the dopamine 1 receptor but significantly reduced the expression of the dopamine 2 receptor in both the nucleus accumbens (NAc) and the dorsal striatum (DSt). We also found that 25 N-NBOMe significantly decreased the expression of the dopamine transporter only in the NAc, while increasing the expression of the phosphorylated dopamine transporter in both the NAc and the DSt. Furthermore, 25 N-NBOMe significantly reduced the expression of tyrosine hydroxylase in the NAc but not in the DSt. Taken together, these findings suggest that 25 N-NBOMe has abuse potential via dopaminergic system.

Isoorientin improves scopolamine-induced cognitive impairments by restoring the cholinergic system, antioxidant defense, and p-CREB/BDNF signaling in the hippocampus and frontal cortex.

Isoorientin (ISO) is considered one of the most important flavonoids with various pharmacological effects such as antioxidant, anti-inflammatory, and anti-cancer activities. Despite these beneficial activities, the effects of ISO on learning and memory have not been investigated so far. The current study evaluated the memory-enhancing effects of ISO in a scopolamine-treated mouse model by using the Y-maze and passive avoidance tests. The results showed that ISO (5 and 10 mg/kg, p.o.) treatment significantly improved the cognitive impairments caused by scopolamine. Additionally, ISO significantly decreased scopolamine-induced acetylcholinesterase and thiobarbituric acid reactive substance activities in both the hippocampus and frontal cortex of mice. In addition, ISO significantly increased the levels of total superoxide dismutase induced by scopolamine in the hippocampus and frontal cortex. Moreover, Western blot results indicated that ISO reversed the decreases in expression of phosphorylated cAMP response element binding (CREB) and brain-derived neurotrophic factor (BDNF) in the hippocampus and frontal cortex of scopolamine-treated mice. Thus, our results provide initial evidence that ISO ameliorates scopolamine-induced memory and cognitive impairments partly by restoring the cholinergic system, antioxidant defense, and p-CREB/BDNF signaling pathway, thereby exhibiting memory-enhancing activities.

7,8,4'-Trihydroxyisoflavone, a Metabolized Product of Daidzein, Attenuates 6-Hydroxydopamine-Induced Neurotoxicity in SH-SY5Y Cells.

Daidzein isolated from soybean (Glycine max) has been widely studied for its antioxidant and anti-inflammatory activities. However, the protective effects of 7,8,4'-trihydroxyisoflavone (THIF), a major metabolite of daidzein, on 6-hydroxydopamine (OHDA)-induced neurotoxicity are not well understood. In the current study, 7,8,4'-THIF significantly inhibited neuronal cell death and lactate dehydrogenase (LDH) release induced by 6-OHDA in SH-SY5Y cells, which were used as an in vitro model of Parkinson' disease (PD). Moreover, pretreatment with 7,8,4'-THIF significantly increased the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) and decreased malondialdehyde (MDA) activity in 6-OHDA-induced SH-SY5Y cells. In addition, 7,8,4'-THIF significantly recovered 6-OHDA-induced cleaved caspase-3, cleaved caspase-9, cleaved poly-ADP-ribose polymerase (PARP), increased Bax, and decreased Bcl-2 levels. Additionally, 7,8,4'-THIF significantly restored the expression levels of phosphorylated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2 (ERK 1/2), phosphatidylinositol 3-kinases (PI3K)/Akt, and glycogen synthase kinase-3 beta (GSK-3ß) in 6-OHDA-induced SH-SY5Y cells. Further, 7,8,4'-THIF significantly increased the reduced tyrosine hydroxylase (TH) level induced by 6-OHDA in SH-SY5Y cells. Collectively, these results suggest that 7,8,4'-THIF protects against 6-OHDA-induced neuronal cell death in cellular PD models. Also, these effects are mediated partly by inhibiting activation of the MAPK and PI3K/Akt/GSK-3ß pathways.

The memory-enhancing effects of 7,8,4'-trihydroxyisoflavone, a major metabolite of daidzein, are associated with activation of the cholinergic system and BDNF signaling pathway in mice.

Daidzein is one of the dietary isoflavones present in soybean-based products. After ingestion, daidzein is bioconverted into its major metabolite, 7,8,4'-trihydroxyisoflavone (THIF). Given the pharmacological importance of daidzein, 7,8,4'-THIF has also attracted the interest of researchers. However, there are no reports on the effects of 7,8,4'-THIF on cognition and memory with regard to the cholinergic system. Therefore, this study sought to evaluate the memory-enhancing effects of 7,8,4'-THIF in mice. Treatment with 7,8,4'-THIF ameliorated the cognitive impairments induced by scopolamine, a muscarinic acetylcholine receptor antagonist, in the Y-maze and passive avoidance tests. Interestingly, 7,8,4'-THIF treatment also improved cognitive function in normal mice. This treatment was also able to reverse acetylcholinesterase (AChE) and thiobarbituric acid reactive substance (TBARS) activities in the hippocampus. Finally, 7,8,4'-THIF significantly increased the expression levels of the following molecules in the hippocampus: brain-derived neurotrophic factor (BDNF); phospho extracellular signal-regulated kinase (ERK); phospho cAMP response element binding (CREB); and choline acetyltransferase (ChAT). Our data suggest that 7,8,4'-THIF, a metabolized product of daidzein, improves cognitive function by activating the cholinergic system and the BDNF/ERK/CREB signaling pathway in mice.

6,7,4'-Trihydroxyisoflavone, a major metabolite of daidzein, improves learning and memory via the cholinergic system and the p-CREB/BDNF signaling pathway in mice.

Daidzein is one of the major isoflavfones found in soy food and plants. Following ingestion, daidzein is readily converted to hydroxylated metabolites in the human body. 6,7,4'-Trihydroxyisoflavone (THIF), one of the metabolites of daidzein, has several pharmacological activities, including anti-cancer and anti-obesity properties. However, no reports exist on the effects of 6,7,4'-THIF for cognitive function in mice. The present study aimed to investigate the effects of 6,7,4'-THIF against scopolamine-induced learning and memory impairments using the Y-maze and passive avoidance test. A single administration of 6,7,4'-THIF significantly improved scopolamine-induced cognitive dysfunction in these in vivo tests. Moreover, treatment with 6,7,4'-THIF alone enhanced learning and memory performance in the same behavioral tests. Molecular studies showed that 6,7,4'-THIF significantly inhibited acetylcholinesterase and thiobarbituric acid reactive substance (TBARS) activities in the hippocampus of scopolamine-induced mice. In addition, immunohistochemistry and Western blot results revealed that 6,7,4'-THIF significantly increased brain-derived neurotrophic factor (BDNF) and phosphor cAMP response element binding (CREB) in the hippocampus of mice. Taken together, these findings suggest that 6,7,4'-THIF improves cognitive dysfunction induced by scopolamine and enhances learning and memory by activation of the cholinergic system and the p-CREB/BDNF signaling pathway in mice.

Repeated restraint stress reduces the acquisition and relapse of methamphetamine-conditioned place preference but not behavioral sensitization.

The studies for the effects of stress on drug addiction were mostly obtained using sequential exposure to stress and drugs. However, few studies have been conducted on the effects of simultaneous exposure to stress and methamphetamine (METH) on METH-induced reward effects and behavioral sensitization. Thus, we examined the effects of simultaneous exposure to restraint stress and METH on METH-induced addictive behaviors using conditioned place preference (CPP) in mice. During the conditioning period, the mice were exposed to 2 h restraint stress before administration of METH or saline for 4 days. To investigate the effect of restraint stress on drug relapse, the mice were exposed to 2 h of restraint stress for 4 days during the late period of withdrawal. The results showed that the acquisition of METH CPP was impaired by simultaneous exposure to restraint stress and METH administration and the impairment of METH CPP was retained until METH-induced reinstatement. Additionally, based on locomotor activity data measured during METH reinstatement, simultaneous stress exposure during the conditioning phase increased METH-induced locomotor sensitization. We also found that the magnitude of METH-primed relapse was reduced in mice exposed to restraint stress during the late period of withdrawal. Taken together, these findings suggest that simultaneous exposure to restraint stress and METH can reduce the acquisition and relapse of METH-induced addictive behaviors but not behavioral sensitization.

Evodiamine Reduces Caffeine-Induced Sleep Disturbances and Excitation in Mice.

Worldwide, caffeine is among the most commonly used stimulatory substances. Unfortunately, significant caffeine consumption is associated with several adverse effects, ranging from sleep disturbances (including insomnia) to cardiovascular problems. This study investigates whether treatment with the Evodia rutaecarpa aqueous extract (ERAE) from berries and its major molecular component, evodiamine, can reduce the adverse caffeine-induced sleep-related and excitation effects. We combined measurements from the pentobarbital-induced sleep test, the open field test, and the locomotor activity test in mice that had been dosed with caffeine. We found that ERAE and evodiamine administration reduced the degree of caffeine-induced sleep disruption during the sleep test. Additionally, we found that evodiamine significantly inhibits caffeine-induced excitation during the open field test, as well as decreasing hyperlocomotion in the locomotor activity test. Additional in vitro experiments showed that caffeine administration decreased the expression of γ-aminobutyric acid (GABA)A receptor subunits in the mouse hypothalamus. However, evodiamine treatment significantly reversed this expression reduction. Taken together, our results demonstrate that ERAE and its major compound, evodiamine, provide an excellent candidate for the treatment or prevention of caffeine-induced sleep disturbances and excitatory states, and that the mechanism of these beneficial effects acts, at least in part, through the GABAA-ergic system.