Fluoxetine Up-Regulates Bcl-xL Expression in Rat C6 Glioma Cells.

OBJECTIVE: To analyze both differentially expressed genes and the Bcl-xL protein expression after acute and chronic treatment with fluoxetine in rat C6 glioma cells. METHODS: C6 glioma cells were cultured for 24 h or 72 h after treatment with 10 µM fluoxetine, and gene expression patterns were observed using microarray and qRT-PCR. Then, cells were cultured for 6 h, 24 h, 72 h or 96 h after treatment with 10 µM fluoxetine, and the expression of Bcl-xL protein was measured using western blot. RESULTS: As determined by microarray, treatment with fluoxetine for 24 h up-regulated 33 genes (including Bcl-xL and NCAM140) and down-regulated 7 genes (including cyclin G-associated kinase). Treatment with fluoxetine for 72 h up-regulated 53 genes (including Gsα and Bcl-xL) and down-regulated 77 genes (including Gαi2 and annexin V). Based on the qRT-PCR results, there was an increase in Gsα mRNA and a decrease in Gαi2 mRNA at 72 h in fluoxetine-treated cells as compared to control, a result that was consistent with microarray. We also observed an increase in Bcl-xL mRNA (both at 24 h and at 72 h) in fluoxetine-treated cells as compared to control, demonstrating a tendency to increase gradually. Bcl-xL protein expression increased as the duration of fluoxetine treatment increased. CONCLUSION: These results suggest that chronic treatment with fluoxetine not only initiates the cAMP pathway through inducing Gsα expression but also induces Bcl-xL expression, thus inhibiting apoptosis.

The Effects of Venlafaxine and Dexamethasone on the Expression of HSP70 in Rat C6 Glioma Cells.

OBJECTIVE: The present study aimed to determine the intracellular action of the antidepressant, venlafaxine, in C6 glioma cells using heat shock protein 70 (HSP70) immunocytochemistry and HSP70 Western blots; HSP70 is known to be associated with stress and depression. METHODS: The extent of HSP70 expression was measured after rat C6 glioma cells were treated with 1) dexamethasone only, 2) venlafaxine only, 3) simultaneous venlafaxine and dexamethasone, or 4) dexamethasone after venlafaxine pretreatment. Dexamethasone (10 microM, 6 hours) did not affect the level of HSP70 expression relative to control. RESULTS: Short-term (1 hour) venlafaxine treatment significantly increased the level of HSP 70 expression. Simultaneous long-term (72 hours) venlafaxine and dexamethasone treatment significantly reduced the level of HSP70 expression. Dexamethasone treatment administered following long-term (24 and 72 hours) pretreatment with venlafaxine also significantly reduced the level of HSP70 expression. CONCLUSION: Short-term treatment with venlafaxine increases the expression of HSP70, but prolonged treatment with dexamethasone suppresses the venlafaxine-induced expression of HSP70. These findings suggest that HSP70 and dexamethasone play a significant role in the pathophysiology of depression.

Effects of haloperidol and risperidone on the expression of heat shock protein 70 in MK-801-treated rat C6 glioma cells.

Non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists such as dizocilpine (MK-801) produce schizophrenia-like psychosis in humans and induce the expression of heat shock protein 70 (HSP70) in rats. The present study examines the effects of antipsychotic drugs, haloperidol and risperidone, on the expression of HSP70 produced by MK-801 in rat C6 glioma cells. After pretreating with haloperidol and risperidone for 1 h, 6 h, 24 h and 72 h, respectively, C6 glioma cells were cultivated again in MK-801 for 6 h, and then, the extent of HSP70 expression was measured by immunoblotting using anti-HSP70 monoclonal antibody. The expression of HSP70 induced by MK-801 significantly decreased as the duration of haloperidol pretreatment was extended (p=0.002). Risperidone also increasingly attenuated the expression of HSP70 produced by MK-801 as the duration of pretreatment grew longer (p=0.003). The present findings show that haloperidol and risperidone decrease the HSP70 expression in MK-801-treated rat C6 glioma cells. These results suggest that HSP70 and NMDA receptors may play a significant role in the pathophysiology of schizophrenia.

Social-cognitive predictors of dietary behaviors in South Korean men and women.

BACKGROUND: Eating a diet that is high in vitamins and low in fat is considered to be governed by social-cognitive factors, such as intentions, planning, self-efficacy, and outcome expectancies. PURPOSE: A longitudinal field study was designed to examine the interrelationships of these factors with dietary behaviors. METHOD: In 697 South Korean men and women, objective health-risk status was assessed at Time 1 (cholesterol, blood pressure, and body mass index) in conjunction with self-efficacy, outcome expectancies, and intentions. At Time 2, six months later, coping self-efficacy, planning, and dietary behaviors were measured. A two-group structural equation model for men and women was specified to determine the relations of distal and proximal predictors of a healthy diet. RESULTS: Self-efficacy was of equal predictive power in men and women, whereas intentions and planning were relevant only in women. Objective risk status was associated with intentions in women but not in men. CONCLUSIONS: Results confirm the predictive power of the Health Action Process Approach and point to the role of gender in the self-regulation of dietary behaviors.

Changes of brain potentials in response to smoking-induced stimuli in smokers.

Changes in P300 amplitude were used as an indicator of reactivity to smoking-related stimuli in smokers. The amplitude of P300--a component of event-related brain potentials (ERPs) elicited by 10 smoking-related (craving), 10 antismoking (aversive) and 10 neutral stimuli-- was recorded in smokers (n=10) and nonsmokers (n=10). Electroencephalography (EEG) data were obtained by the Laxtha EEG-monitoring device in the EEG recording room, and were recorded at F3, F4, C3, and C4. Three-way repeated-measures analysis of variance (ANOVA) was computed on the P300 amplitudes. The factors were group (smokers, nonsmokers), stimulus (craving, aversive, neutral), and electrode location (F3, F4, C3, and C4). The main effects of stimulus were significant, but the group effects did not show significant interactions with other factors. An interesting observation was the similarity between P300 waveforms for craving and aversive stimuli in smokers. These findings could indicate that the antismoking-related response is similar to the smoking-related one.

Naltrexone influences protein kinase Ce and integrin alpha7 activity in SH-SY5Y neuroblastoma cells.

Alcohol influences the neuroadaptation of brain cells where receptors and enzymes like protein kinase C (PKC) exist. Naltrexone acts on opioid receptors. However, other mechanisms of action remain unknown. We prepared SH-SY5Y neuroblastoma cells, and fed them with 150 mM ethanol for 72 h followed by treatment with naltrexone for 24 h. We performed microarray analysis and reverse transcriptase-polymerase chain reaction. Our results showed that PKCepsilon increased 1.90 times and showed an overall decreasing pattern as time increased. Phosphorylated ERK also increased 2.0 times according to the change of PKCepsilon. Integrin alpha7 increased 2.32 times and showed an increasing pattern as time increased. In conclusion, naltrexone influences PKCepsilon neuronal signaling system and endothelial adhesion molecule integrin alpha7 in addition to the well-known opioid system.

Fluoxetine-induced up-regulation of 14-3-3zeta and tryptophan hydroxylase levels in RBL-2H3 cells.

The primary mechanisms of antidepressants are based on the monoamine depletion hypothesis. However, we do not yet know the full cascade of mechanisms responsible for the therapeutic effect of antidepressants. To identify the genes involved in the therapeutic mechanism of the selective serotonin reuptake inhibitor, fluoxetine, we used a cDNA microarray analysis with RBL-2H3 cells. We observed the transcriptional changes of several tens of genes containing the 14-3-3zeta gene in the fluoxetine-treated RBL-2H3 cells. Real-time RT-PCR and Western blotting confirmed changes in the expression of the gene and protein. The increase of 14-3-3zeta mRNA was observed at 72 h in the fluoxetine-treated RBL-2H3 cells. The increase of 14-3-3zeta protein was observed at 48 and 72 h. In this study, the expressions of the 14-3-3zeta gene and the protein were up-regulated at 72 h. In addition, the increase of TPH mRNA was observed at 12, 24 and 72 h in the fluoxetine-treated RBL-2H3 cells. We conclude that fluoxetine induces increases of 14-3-3zeta mRNA, 14-3-3zeta protein and TPH mRNA at 72 h in the RBL-2H3 cells. This suggests that the 14-3-3zeta and TPH genes may play a role in the molecular mechanism of fluoxetine. To date, no cases of 14-3-3zeta alterations by antidepressants and specifically by fluoxetine have been reported.

Dexamethasone inhibits proliferation of adult hippocampal neurogenesis in vivo and in vitro.

Activation of glucocorticoid receptor (GR) induces a reduction of adult hippocampal neurogenesis found in dentate gyrus (DG). However, the nature of specific effects by glucocorticoid in hippocampal neurogenesis is not known. In this report, we show differential effects of dexamethasone (DEX), a glucocorticoid receptor agonist, on proliferation and functional differentiation of adult hippocampal progenitor cells in DG. Two-month-old adult rats received daily injections of DEX for 9 days and were sacrificed 12 h and 28 days after the ninth injection. Proliferation assays showed that DEX inhibited proliferation of neural progenitor cells and the inhibitory effects of DEX was not detected 28 days after recovery. Functional differentiation studies using B-cell lymphoma protein-2 (Bcl-2), brain-derived neurotrophic factor (BDNF), p-ERK, and neuronal nuclear protein (NeuN) antibodies revealed that the expressions of Bcl-2 and BDNF were not significantly different between control and DEX-treated rats. In contrast, however, the activation of extracellular signal-regulated kinase (ERK) was downregulated 12 h, but not 28 days, after the DEX treatment. When adult hippocampal progenitor cell cultures were treated with subchronic DEX, proliferation of the progenitor cells was suppressed. Taken these in vitro and in vivo results together, it is concluded that glucocorticoid receptor activation blocks only proliferation, but not differentiation, in hippocampal neurogenesis.

Phosphorylation of ERK and CREB in cultured hippocampal neurons after haloperidol and risperidone administration.

The purpose of the present paper was to determine whether the brief exposure of neurons to antipsychotic drugs is associated with the activation of extracellular signal-regulated kinases (ERK) and cyclic adenosine 3',5'-monophosphate (cAMP) response element (CRE) binding protein (CREB). The activation of ERK-1/2 and CREB can be monitored by immunoblotting with antibodies that specifically recognize p-ERK-1/2 (phosphorylated on Thr-202 and Tyr-204) and p-CREB (phosphorylated on Ser-133). In hippocampal neuron cultures at 25 days in vitro (DIV), the levels of ERK and CREB phosphorylation significantly increased after treatment with haloperidol (50 nmol/L) and risperidone (50 nmol/L), except when risperidone was administered at the p-CREB level. However, risperidone also increased the p-CREB level at an insignificant rate in the same direction. At 10 DIV, none of the antipsychotic drugs significantly increased the level of ERK and CREB phosphorylation. The difference between levels of ERK and CREB phosphorylation in response to haloperidol and risperidone at 25 DIV was also observed. Risperidone significantly increased the level of ERK-1/2 phosphorylation, but not the level of CREB phosphorylation. Haloperidol, in contrast, had a different effect. These data indicate that neuronal maturation affects the phosphorylation of ERK and CREB in response to antipsychotic drugs. Furthermore, these results demonstrate that different antipsychotic drugs could lead to different profiles of ERK and CREB phosphorylation in neurons.

Experimental application of virtual reality for nicotine craving through cue exposure.

Research has shown that many smokers experience an increase in the desire to smoke when exposed to smoking-related cues. Cue exposure treatment (CET) refers to the manualized, repeated exposure to smoking-related cues, aimed at the reducing cue reactivity by extinction. In this study, we constructed a virtual reality system for evoking a desire of nicotine, which was based on the results of a Questionnaire of Nicotine-craving. And we investigated the effectiveness of the virtual reality system as compared to classical device (pictures). As a result, we reached the conclusion that virtual reality elicits more craving symptoms than the classical devices.