• Toxicological Research
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• v.9 no.2
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• pp.207-215
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• 1993

Lead is an environmental toxicant that causes a marked deficit in cognative development in infants and children. Damage to the hippocampus has been linked to the lead-induced deficit in the learning process. The present study examined the effects of lead on the development of hippocampal neurons in vitro. Hippocampal neurons were incubated with various concentrations in lead acetate (1nM to 30 nM) for 72 hrs from 4 h after plating, and the percentage of living neurons bearing neurites, neurite outgrowth and migration of multipolar neurons in culture were determined.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.177-186
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• 1998

While tubal pregnancy is frequently observed in human, it has been reported to rarely occur in other mammals. To investigate the reason of the absence of tubal pregnancy in other mammals, the ability of bovine tubal(oviductal) fluid to su, pp.rt the outgrowth of mouse embryos waw examined by using an in vitro model system wherein the trophoblast cells of hatched mouse blastocysts attach to and outgrow on tissue culture plates coated with FBS. When mouse blastocysts grwon in vitro from 2-cell embryos were cultrued in the dishes coated with FBS, human follicular fluid(hFF) and bovine follicular fluid(bFF), respectively, underwent outgrowth by spreading onto the plastic dishes during 48 hr. In contrast, none of the embryos cultured in the dishes coated with BSA or bovine obiductal fluid(bOF) did outgrow but remained as late blastocysts. Since addition of bOF at 5mg/ml or higher conc. to the culture medium resulted in degeneration of all embryos during 48 hr culture, 10mM conc. of glutathione(GSH) was added to the bOF-containing medium to circumvent the toxicity of bOF. In addition, bOF was heated $65^{\circ}C$ for 30 min(hbOF) to get rid of its precipitating properties and then added to the culture medium. When blastocysts were cultured in the presence of both hbOF and GSH 45.4% of embryos attached to the culture dishes. However, none of these embryos underwent outgrowth. Fially embryos were cultured in the presence of both hbOF and GSH but in the dishes coated with FBS. When they were examined after 48 hr, all of the blastocysts exhibited well-developed outgrwoth. Based upon these results, it is concluded that bovine oviductal fluid is capable of su, pp.rting the attchment of mouse blastocysts onto the culture plaste whereas it cannot promote the outgrwoth of mouse blastocysts in vitro, probably due to the lack of outgrwoth factor.

• The Korea Journal of Herbology
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• v.30 no.2
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• pp.43-48
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• 2015

Objectives : The aim of this study was to investigate the memory enhancing properties of extract of Hoelen Cum Radix (HCR) and its possible mechanism in mice of normal condition. Methods : We evaluated the effects of HCR on cognitive function and memory enhancement in normal mice. Male ICR mice were orally administrated with HCR 100 mg/kg for 7 days and equal volume of saline was administrated to the control group in the same condition. We conducted two behavioral tests which measure the spatial working memory (Y-maze test) and cognitive fear memory (passive avoidance test). We also investigated whether HCR affects the hippocampal neurogenesis in the brain. To assess the effects of HCR on neural progenitor cell differentiation and neurite outgrowth in the early stage of hippocampal neurogenesis, we performed doublecortin (DCX), a direct neurogenesis marker, immunohistochemical analysis in the dentate gyrus (DG) of the mouse hippocampus. Results : HCR significantly enhanced memory and cognitive function as determined by the Y-maze test (p<0.05) and passive avoidance test (p<0.001). Moreover, HCR increased DCX positive cells (p<0.01) and neurite length (p<0.01) compared to the control group. These results indicated that HCR stimulates differentiation of neural progenitor cells and promotes neurite outgrowth in hippocampal DG of the mice. Conclusion : We concluded that HCR shows memory enhancing effects through the stimulation of hippocampal neurogenesis as a consequence of accelerated neuronal differentiation and neurite outgrowth in the DG of the hippocampus after HCR treatment.

• BMB Reports
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• v.31 no.5
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• pp.468-474
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• 1998

Membrane depolarization in PC12 cells induces calcium influx via an L-type voltage-sensitive calcium channel (L-VSCC) and increases intracellular free calcium, which leads to tyrosine phosphorylation of epidermal growth factor (EGF) receptor and the associated adaptor protein, She. This activated EGF receptor complex then can activate mitogen-activated protein (MAP) kinase, as in nerve growth factor (NGF) receptor activation. In the present study, we investigated the role of EGF receptor in the signaling pathway initiated by membrane depolarization of PC12 cells. Prolonged membrane depolarization induced phosphorylation of extracellular signal-regulated kinase (ERK) within 1 min in undifferentiated PC12 cells. Pretreatment of PC12 cells with the calcium chelator EGTA abolished depolarization-stimulated ERK phosphorylation, but NGF-induced phosphorylation of ERK was not affected. The chronic treatment of phorbol ester, which down-regulated the activity of protein kinase C (PKC), did not affect the phosphorylation of ERK upon depolarization. In the presence of an inhibitor of EGF receptor, neither depolarization nor calcium ionophore increased the level of ERK phosphorylation. These data imply that the EGF receptor is functionally necessary to activate ERK and neurite outgrowth in response to the prolonged depolarization in PC12 cells, and also that PKC is apparently not involved in this signaling pathway.

• BMB Reports
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• v.40 no.6
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• pp.888-894
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• 2007

Src homology (SH) domains of phospholipase C-$\gamma1$ (PLC-$\gamma1$) impair NGF-mediated PC12 cells differentiation. However, whether the enzymatic activity is also implicated in this process remains elusive. Here, we report that the enzymatic activity of phospholipase C-$\gamma1$ (PLC-$\gamma1$) is at least partially involved to the blockage of neuronal differentiation via an abrogation of MAPK activation, as well as sustained Akt activation. By contrast, Overexpression of WT-PLC-$\gamma1$ exhibited sustained NGF-induced MAPK activation, and triggered transient Akt activation resulting in profound inhibition of neurite outgrowth. However, lipase-inactive mutant (LIM) PLC-$\gamma1$ cells fail to suppress neurite outgrowth, although it contains intact SH domains, specifically enhancing the expression of cyclin D1 and p21 proteins, which regulate the function of retinoblastoma Rb protein. These observations show that the lipase inactive mutant of PLC-$\gamma1$ does not alter NGF-induced neuronal differentiation via enzymatic inability and the modulation of cell cycle regulatory proteins independent on SH3 domain.

• Biomolecules & Therapeutics
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• v.24 no.5
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• pp.469-474
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• 2016

Liriopogons (Liriope and Opiopogon) species are used as a main medicinal ingredient in several Asian countries. The Liriopes Radix (tuber, root of Liriope platyphylla) has to be a promising candidate due to their source of phytochemicals. Steroidal saponins and their glycosides, phenolic compounds, secondary metabolites are considered of active constituents in Liriopes Radix. Spicatoside A, a steroidal saponin, could be more efficacious drug candidate in future. In this review, we summarized the available knowledge on phytochemical and pharmacological activities for spicatoside A. It significantly suppressed the level of NF-${\kappa}B$, NO, iNOS, Cox-2, IL-$1{\beta}$, IL-6 and MAPKs in LPS-stimulated inflammation. The production of MUC5AC mucin was increased. MMP-13 expression was down-regulated in IL-$1{\beta}$-treated cells and reduced glycosaminoglycan release from IL-$1{\alpha}$-treated cells. The neurite outgrowth activity, PI3K, Akt, ERK1/2, TrkA and CREB phosphorylation and neurotropic factors such as NGF and BDNF were upregulated with increased latency time. It also showed cell growth inhibitory activity on various carcinoma cells. From this, spicatoside A exerts anti-inflammation, anti-asthma, anti-osteoclastogenesis, neurite outgrowth, memory consolidation and anticancer activities. Further studies are needed on spicatoside A in order to understand mechanisms of action to treat various human diseases.

• Korean Journal of Pharmacognosy
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• v.34 no.4 s.135
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• pp.282-287
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• 2003

We reported that neurotoxicity may contribute to cyanide-induced neuronal injury. Cyanide stimulates the release of glutamate which can activate glutamate receptors to propagate excitotoxic processes. We examined the role of plant extracts in mediating the cyanide-induced cytotoxicity and report here that the cytotoxicity assessed in SK- N-SH cell cultures by measuring lactate dehydrogenase (LDH) in the culture media was significantly blocked by Evodia officinalis MeOH extract (OMU). Also, when OMU was treated in NaCN level cultures, the neurite outgrowth was regenerated as much as in the treatment of NaCN only. These results indicate that OMU treatment were not only protected the neurons against NaCN-induced damage but also regenerated the neurite outgrowth of neuroblastoma cells.

• Journal of Mushroom
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• v.11 no.3
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• pp.117-123
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• 2013

Hot water soluble extract was prepared from Hericium erinaceus and its neuritogenic activity on PC12h cells was analyzed, which is a clone originating from a rat pheochromocytomon. The moisture content of freeze dried hot water extract was 12.08%. The extract was mainly composed of carbohydrate (51.24%) followed by crude protein (24.04%), crude fat (0.26%), dietary fiber (5.09), and ash (12.18%). Fatty acids, glucan and inorganic constituents were found as minor components. The neuritogenic activity of hot water extract was evaluated under microscopic observation of neurite outgrowth in PC12h cells and by measuring the neurite length of induvidual cell. The extract exhibited strong effect of neurite outgrowth in a dose-dependent manner from 0.01 mg/mL to 1 mg/mL, in which longer neurite outgrowth was observed as the treatment dose increased.

• Biomedical Science Letters
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• v.13 no.3
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• pp.197-206
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• 2007

P2X receptors are membrane-bound ion channels that conduct $Na^+,\;K^+$, and $Ca^{2+}$ in response to ATP and its analogs. There are seven subunits identified so far ($P2X_1-P2X_7$). $P2X_2$ receptors are known to be expressed in a wide range of organs including brains and adrenal grands. PC12 cells are originated from adrenal grand and differentiated by nerve growth factor or pituitary adenylate cyclase activating poly peptide (PACAP). Previous studies indicate that $P2X_2$ receptor activation in PC12 cells couples to $Ca^{2+}-dependent$ release of catecholamine and ATP. It is known that acidic pH potentiates ATP currents at $P2X_2$ receptors. This leads to a hypothesis that $P2X_2$ receptors may play an important role in PC12 cell differentiation, one of the characteristics of which is neurite outgrowth, induced by the hormones under lower pH. In the present study, we isolated several clones which potentiate neurite outgrowth by PACAP in acidic pH (6.8), but not in alkaline pH (7.6). RT-PCR and electrophysiology data indicate that these clones express only functional $P2X_2$ receptors in the absence or presence of PACAP for 3 days. Potentiation of neurite outgrowth resulted from PACAP (100 nM) in acidic pH is inhibited by the two P2X receptor antagonists, suramin and PPADS ($100\;{\mu}M)$ each), and exogenous exprerssion of ATP-binding mutant $P2X_2$ receptor subunit ($P2X_2[K69A]$). However, acid sensing ion channels (ASICs) are not involved in PACAP-induced neurite outgrowth potentiation in lower pH since treatments of an inhibitor of ASICs, amyloride ($10\;{\mu}M$), did not give any effects to neurite extension. The vesicular proton pump ($H^+-ATPase$) inhibitor, bafilomycin (100 nM), reduced neurite extension indicating that ATP release resulted from $P2X_2$ receptor activation in PC12 cells is needed for neurite outgrowth. These were confirmed by activation of mitogen activated protein kinases, such as ERKs and p38. These results suggest roles of ATP and $P2X_2$ receptors in hormone-induced cell differentiation or neuronal synaptogenesis in local acidic environments.

• Journal of Life Science
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• v.31 no.9
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• pp.806-817
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• 2021

Increasing evidence suggests that depression is associated with impairments in neural plasticity. Sirtuin 1 plays an important role in neural plasticity, and the activation of mechanistic target of rapamycin complex 1 (mTORC1) signaling is known to improve neural plasticity. In this study, we aimed to determine whether sirtuin 1 affects dendrite outgrowth and spine formation through mTORC1 signaling. Resveratrol (sirtuin 1 activator; 1 and 10 μM) and sirtinol (sirtuin 1 inhibitor; 1 and 10 μM) were treated in primary cortical culture with and without dexamethasone (500 μM). Levels of sirtuin 1, phospho-extracellular signal regulated protein kinase 1/2 (ERK1/2), phospho-mTORC1, and phospho-p70 ribosomal protein S6 kinase (p70S6K) were evaluated using Western blot analysis. Dendritic outgrowth and spine density were assessed using immunostaining. Resveratrol significantly increased levels of sirtuin 1 expression and phosphorylation of ERK1/2 (a downstream target of sirtuin 1), mTORC1, and p70S6K (a downstream target of mTORC1) in a concentration-dependent manner under dexamethasone conditions. Resveratrol also significantly increased dendritic outgrowth and spine density. Conversely, sirtinol significantly decreased levels of sirtuin 1 expression and phosphorylation of ERK1/2, mTORC1, and p70S6K in a concentration-dependent manner under normal conditions. Moreover, sirtinol significantly decreased dendritic outgrowth and spine density. Consistent with the results of sirtinol, sirtuin 1 knockdown using sirtuin 1 siRNA transfection significantly decreased dendritic outgrowth and spine density as well as phosphorylation levels of ERK1/2 and mTORC1. These data suggest that sirtuin 1 enhances dendritic outgrowth and spine density by activating mTORC1 signaling.