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Acute Ethanol (acute + ethanol)
Selected AbstractsAcute Ethanol Inhibits Extracellular Signal,Regulated Kinase, Protein Kinase B, and Adenosine 3,:5,-Cyclic Monophosphate Response Element Binding Protein Activity in an Age- and Brain Region,Specific MannerALCOHOLISM, Issue 4 2005L Judson Chandler Background: As little as a single episode of exposure of the developing brain to ethanol can result in developmental neuropathology and mental retardation. Extracellular signal,regulated kinases (ERKs), protein kinase B (PKB), and adenosine 3,:5,-cyclic monophosphate response element binding protein (CREB) are messenger molecules that play important roles in neuronal plasticity and survival. This study was undertaken to examine the effects of acute ethanol on ERK, PKB, and CREB activation in the brain. Methods: Immunoblot analysis was used to determine the effects of a 1-hr exposure of ethanol on levels of phospho-ERC in primary cortical cultures and in the cerebral cortex, hippocampus, and cerebellum of postnatal day 5 (PN5), postnatal day 21 (PN21), and adult rats. Results: In cortical cultures, ethanol (100 mM) significantly reduced activity-dependent activation of phospho-ERK, phospho-PKB, and phospho-CREB by approximately 50%. In PN5 rats, ethanol (3.5 g/kg) inhibited both phospho-ERK and phospho-PKB in the cerebral cortex and hippocampus but was without effect in the cerebellum. A similar brain region,specific inhibition of phospho-ERK was observed in PN21 rats, whereas in adult rats, ethanol inhibited phospho-ERK in all three brain regions. In contrast, ethanol had no effect on phospho-PKB in either PN21 or adult rats. Without exception, ethanol inhibited phospho-CREB in an identical brain region, and age-dependent manner as was observed for phospho-ERK. Finally, administration of the NMDA antagonist MK-801 (0.5 mg/kg) to PN5 rats had no effect on phospho-ERK or phospho-PKB levels in any brain region. Conclusion: The results demonstrate that acute ethanol inhibits ERK/PKB/CREB signaling in brain. This inhibition occurs in an age- and brain region,specific manner, with inhibition of PKB restricted to a time during the brain growth-spurt period. Furthermore, the lack of effect of MK-801 suggests that inhibition of NMDA receptors is unlikely to play a major role in binge ethanol inhibition of ERK/PKB/CREB signaling in vivo. [source] Alcohol Effects on Central Nervous System Gene Expression in Genetic Animal ModelsALCOHOLISM, Issue 2 2005William J. McBride This article summarizes the proceedings of a symposium presented at the 2004 annual meeting of the Research Society on Alcoholism in Vancouver, British Columbia, Canada. The organizers and chairs were William J. McBride and Michael F. Miles. The presentations were (1) Molecular Triangulation on Gene Expression Patterns in Behavioral Responses to Acute Ethanol, by Robnet T. Kerns; (2) Gene Expression in Limbic Regions After Ethanol Self-Infusion Into the Posterior Ventral Tegmental Area, by Zachary A. Rodd; (3) Microarray Analysis of CNS Limbic Regions of Inbred Alcohol-Preferring and -Nonpreferring rats and Effects of Alcohol Drinking, by Wendy N. Strother and Howard J. Edenberg; and (4) Microarray Analysis of Mouse Lines Selected for Chronic Ethanol Withdrawal Severity: The Convergence of Basal, Ethanol Regulated, and Proximity to Ethanol Quantitative Trait Loci to Identify Candidate Genes, by Joel G. Hashimoto and Kristine M. Wiren. [source] Differential Changes in MAP Kinases, Histone Modifications, and Liver Injury in Rats Acutely Treated With EthanolALCOHOLISM, Issue 9 2010Annayya R. Aroor Background:, Acute ethanol is known to affect cells and organs but the underlying molecular mechanisms are poorly explored. Recent developments highlight the potential importance of mitogen-activated protein kinases, MAPKs (i.e., ERK1/2, p38, and JNK1/2) signaling, and histone modifications (i.e., acetylation, methylation, and phosphorylation) in the actions of ethanol in hepatocytes. We have therefore investigated significance of these molecular steps in vivo using a model in which rats were acutely administered ethanol intraperitoneally (IP). Methods:, Ethanol was administered IP (3.5 gm/kg body weight) to 12-week-old male Sprague,Dawley rats. Liver was subsequently removed at 1 and 4 hours. Serum was used for alcohol and ALT assays. At the time of the removal of liver, small portions of each liver were formalin-fixed and stained with hematoxylin and eosin (H&E) and used for light microscopy. Western blot analysis was carried out with specific primary antibodies for various parameters. Results:, There were clear differences at 1 and 4 hours in blood ethanol, ALT, steatosis, and cleaved caspase 3. Apoptosis at 1 hour was followed by necrosis at 4 hours. Acute alcohol elicited a marked increase in the phosphorylation of ERK1/2 and moderate increases in the phosphorylation of p38 MAPK and JNK. Temporally different phosphorylation of histone H3 at ser-10 and ser-28 occurred and acetylation of histone H3 at lys 9 increased progressively. Conclusions:, There were distinct differences in the behavior of the activation of the 3 MAP kinases and histone modifications after acute short exposure of liver to ethanol in vivo. Although all 3 MAPKs were rapidly activated at 1 hour, the necrosis, occurring at 4 hours, correlated to sustained activation of ERK1/2. Transient activation of p38 is associated with rapid phosphorylation of histone H3, whereas prolonged activation of ERK1/2 is correlated to persistent histone H3 acetylation. [source] Disparity Between Tonic and Phasic Ethanol-Induced Dopamine Increases in the Nucleus Accumbens of RatsALCOHOLISM, Issue 7 2009Donita L. Robinson Background:, Dopamine concentrations in the nucleus accumbens fluctuate on phasic (subsecond) and tonic (over minutes) timescales in awake rats. Acute ethanol increases tonic concentrations of dopamine, but its effect on subsecond dopamine transients has not been fully explored. Methods:, We measured tonic and phasic dopamine fluctuations in the nucleus accumbens of rats in response to ethanol (within-subject cumulative dosing, 0.125 to 2 g/kg, i.v.). Results:, Microdialysis samples yielded significant tonic increases in dopamine concentrations at 1 to 2 g/kg ethanol in each rat, while repeated saline infusions had no effect. When monitored with fast scan cyclic voltammetry, ethanol increased the frequency of dopamine transients in 6 of 16 recording sites, in contrast to the uniform effect of ethanol as measured with microdialysis. In the remaining 10 recording sites that were unresponsive to ethanol, dopamine transients either decreased in frequency or were unaffected by cumulative ethanol infusions, patterns also observed during repeated saline infusions. The responsiveness of particular recording sites to ethanol was not correlated with either core versus shell placement of the electrodes or the basal rate of dopamine transients. Importantly, the phasic response pattern to a single dose of ethanol at a particular site was qualitatively reproduced when a second dose of ethanol was administered, suggesting that the variable between-site effects reflected specific pharmacology at that recording site. Conclusions:, These data demonstrate that the relatively uniform dopamine concentrations obtained with microdialysis can mask a dramatic heterogeneity of phasic dopamine release within the accumbens. [source] Influence of Genetically Predisposed Diabetes on Ethanol-Induced Depression of Cardiac Contraction in Adult Rat Ventricular MyocytesEXPERIMENTAL PHYSIOLOGY, Issue 3 2002Jun Ren Diabetes mellitus and alcohol (ethanol) intake are two positively correlated major risk factors for cardiovascular abnormalities. However, the interaction of the two on cardiac function is largely unknown. The purpose of the present study was to examine the impact of genetically predisposed diabetes on acute ethanol exposure-induced cardiac contractile depression at the myocyte level. Ventricular myocytes from spontaneously biobreeding diabetes-prone (BBDP) rats and their diabetes-resistant littermates (BBDR) were stimulated to contract at 0.5 Hz. Contractile properties analysed include: peak shortening amplitude (PS), time-to-PS (TPS), time-to-90% relengthening (TR90) and maximal velocities of shortening/relengthening (± dL/dt). BBDP rats displayed hyperglycaemia, reduced body weight gain and increased cardiac, hepatic and renal size. Myocytes isolated from BBDP rat hearts exhibited prolonged TPS and TR90 associated with normal PS and ± dL/dt, compared with myocytes from the BBDR group. Acute ethanol exposure (80-640 mg dl,1) caused a concentration-dependent inhibition of PS in both BBDR and BBDP myocytes. However, the degree of inhibition of PS was significantly reduced in BBDP myocytes compared to that of BBDR myocytes. The maximal inhibition was 52.9% and 28.4% in BBDR and BBDP groups, respectively. Ethanol significantly depressed ± dL/dt in both BBDR and BBDP myocytes. In addition, ethanol did not affect TPS or TR90 in either the BBDR or BBDP group. Collectively, these results suggest that the ethanol-induced depression in cardiac myocyte contraction may be ,shadowed' by genetically predisposed diabetes. [source] Ethanol enhancement of cocaine- and amphetamine-regulated transcript mRNA and peptide expression in the nucleus accumbensJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Armando Salinas Abstract Cocaine- and amphetamine-regulated transcript (CART) is a peptide neurotransmitter that has been implicated in drug reward and reinforcement. CART mRNA and peptide expression are highly concentrated in several compartments of the mesolimbic reward pathway. Several lines of evidence suggest that CART peptides may contribute to rewarding behaviors and the addiction liability of psychostimulants; however, there are no reports of basic work concerning CART in relation to alcohol and mechanisms of alcohol dependence development. Therefore, in this study we investigated the response of CART transcript and peptide to acute ethanol administration in vivo. Rats were administered ethanol (1 g/kg or 3.5 g/kg, 1 h, ip) and CART expression was measured by RT-PCR in the nucleus accumbens (NAcc). Ethanol (3.5 g/kg) increased CART transcription markedly. The interactions of dopamine on ethanol-induced CART expression were further evaluated pharmacologically using D1 and D2/D3 receptor antagonists. Both SCH 23390 (0.25 mg/kg) or raclopride (0.2 mg/kg) pre-treatment significantly suppressed ethanol-enhancement of CART mRNA transcription. Confocal immunofluorescence microscopy revealed that CART peptide immunoreactivity was also enhanced in both the core and the shell of the NAcc by ethanol administration. These findings demonstrate that CART mRNA and peptide expression are responsive to acute ethanol administrated in vivo and suggests that CART peptides may be important in regulating the rewarding and reinforcing properties of ethanol. [source] Differential Effects of Acute and Chronic Ethanol Exposure on Orexin Expression in the Perifornical Lateral HypothalamusALCOHOLISM, Issue 5 2010Irene Morganstern Background:, Recent reports support the involvement of hypothalamic orexigenic peptides in stimulating ethanol intake. Our previous studies have examined the effects of ethanol on hypothalamic peptide systems of the paraventricular nucleus (PVN) and identified a positive feedback loop in which PVN peptides, such as enkephalin and galanin, stimulate ethanol intake and ethanol, in turn, stimulates the expression of these peptides. Recently, orexin (OX), a peptide produced mainly by cells in the perifornical lateral hypothalamus (PFLH), has been shown to play an important role in mediating the rewarding aspects of ethanol intake. However, there is little evidence showing the effects that ethanol itself may have on the OX peptide system. In order to understand the feedback relationship between ethanol and the OX system, the current investigation was designed to measure OX gene expression in the PFLH following acute as well as chronic ethanol intake. Methods:, In the first experiment, Sprague,Dawley rats were trained to voluntarily consume a 2 or 9% concentration of ethanol, and the expression of OX mRNA in the PFLH was measured using quantitative real-time polymerase chain reaction (qRT-PCR). The second set of experiments tested the impact of acute oral gavage of 0.75 and 2.5 g/kg ethanol solution on OX expression in the PFLH using qRT-PCR, as well as radiolabeled in situ hybridization. Further tests using digoxigenin-labeled in situ hybridization and immunofluorescence histochemistry allowed us to more clearly distinguish the effects of acute ethanol on OX cells in the lateral hypothalamic (LH) versus perifornical (PF) regions. Results:, The results showed chronic consumption of ethanol versus water to dose-dependently reduce OX mRNA in the PFLH, with a larger effect observed in rats consuming 2.5 g/kg/d (,70%) or 1.0 g/kg/d (,50%) compared to animals consuming 0.75 g/kg/d (,40%). In contrast to chronic intake, acute oral ethanol compared to water significantly enhanced OX expression in the PFLH, and this effect occurred at the lower (0.75 g/kg) but not higher (2.5 g/kg) dose of ethanol. Additional analyses of the OX cells in the LH versus PF regions identified the former as the primary site of ethanol's stimulatory effect on the OX system. In the LH but not the PF, acute ethanol increased the density of OX-expressing and OX-immunoreactive neurons. The increase in gene expression was detected only at the lower dose of ethanol (0.75 g/kg), whereas the increase in OX peptide was seen only at the higher dose of ethanol (2.5 g/kg). Conclusion:, These results lead us to propose that OX neurons, while responsive to negative feedback signals from chronic ethanol consumption, are stimulated by acute ethanol administration, most potently in the LH where OX may trigger central reward mechanisms that promote further ethanol consumption. [source] Acute and Chronic Ethanol Modulate Dopamine D2-Subtype Receptor Responses in Ventral Tegmental Area GABA NeuronsALCOHOLISM, Issue 5 2009Kimberly H. Ludlow Background:, Ventral tegmental area (VTA) ,-aminobutyric acid (GABA) neurons appear to be critical substrates underlying the acute and chronic effects of ethanol on dopamine (DA) neurotransmission in the mesocorticolimbic system implicated in drug reward. VTA GABA neuron firing rate is reduced by acute ethanol and enhanced by DA via D2 receptor activation. The objective of this study was to evaluate the role of D2 receptors in acute ethanol inhibition of VTA GABA neuron activity, as well as the adaptation of D2 receptors by chronic ethanol consumption. Methods:, Using electrophysiological methods, we evaluated the effects of intraperitoneal ethanol on DA activation of VTA GABA neurons, the effects of DA antagonists on ethanol inhibition of their firing rate, as well as adaptations in firing rate following chronic ethanol consumption. Using single cell quantitative RT-polymerase chain reaction (PCR), we evaluated the expression of VTA GABA neuron D2 receptors in rats consuming ethanol versus pair-fed controls. Results:, In acute ethanol studies, microelectrophoretic activation of VTA GABA neurons by DA was inhibited by acute intraperitoneal ethanol, and intravenous administration of the D2 antagonist eticlopride blocked ethanol suppression of VTA GABA neuron firing rate. In chronic ethanol studies, while there were no signs of withdrawal at 24 hours, or significant adaptation in firing rate or response to acute ethanol, there was a significant down-regulation in the expression of D2 receptors in ethanol-consuming rats versus pair-fed controls. Conclusions:, Inhibition of DA activation of VTA GABA neuron firing rate by ethanol, as well as eticlopride block of ethanol inhibition of VTA GABA neuron firing rate, suggests an interaction between ethanol and DA neurotransmission via D2 receptors, perhaps via enhanced DA release in the VTA subsequent to ethanol inhibition of GABA neurons. Down-regulation of VTA GABA neuron D2 receptors by chronic ethanol might result from persistent DA release onto GABA neurons. [source] Acute Ethanol Exposure Combined With Burn Injury Enhances IL-6 Levels in the Murine IleumALCOHOLISM, Issue 10 2007Michael T. Scalfani Background:, Recent studies suggest that ethanol use imposes a greater risk of trauma-associated intestinal injury than trauma alone. The initiating and regulatory factors for multiple organ dysfunction syndromes are not well defined, yet evidence points to the gut as a possible trigger of the systemic inflammatory cascade as well as a potential source of cytokines. In the current study, we hypothesized that ethanol administration would alter cytokine levels and intestinal infiltration by neutrophils within the ileum of mice exposed to burn injury (15% total body surface of dorsal skin). Methods:, Ileal samples were collected for histological assessment, myeloperoxidase quantitation and the protein presence of tumor necrosis factor alpha (TNF,), interleukin (IL-) 6, macrophage inflammatory protein-2 (MIP-2; CXCL2) and the anti-inflammatory cytokine, IL-10. Additional ileal tissue samples were examined for localization of the IL-6 immunoreactivity. Results:, We did not detect statistically significant cytokine/chemokine differences (MIP-2 and IL-10) between sham control and treatment conditions at either 2 or 24 hours. However, there was a significant decrease in TNF, at 24 hours in both burn injury alone and in combination with ethanol treatment conditions (p < 0.05). In addition, there was an increase in IL-6 levels at 24 hours in intestinal tissue obtained from mice subjected to a combination of acute ethanol and burn injury, compared to the mice receiving burn or sham injury (p < 0.001). Ileal homogenate increases in IL-6 at 24 hours were concurrent with decreased villus height in the ileum, but no discernable changes in neutrophil infiltration (myeloperoxidase activity levels) at either 2 or 24 hours. Additional immunocytochemical localization studies of ileal tissue revealed that there was a substantial increase of IL-6 in intestinal enterocytes subjected to both burn injury alone, or in combination with acute ethanol exposure. Conclusions:, The present study suggests that acute ethanol exposure combined with burn injury enhances levels of IL-6 protein in the ileum. The enhanced levels of ileal IL-6 are likely due to enterocyte production of the cytokine. [source] Acute Ethanol Inhibits Extracellular Signal,Regulated Kinase, Protein Kinase B, and Adenosine 3,:5,-Cyclic Monophosphate Response Element Binding Protein Activity in an Age- and Brain Region,Specific MannerALCOHOLISM, Issue 4 2005L Judson Chandler Background: As little as a single episode of exposure of the developing brain to ethanol can result in developmental neuropathology and mental retardation. Extracellular signal,regulated kinases (ERKs), protein kinase B (PKB), and adenosine 3,:5,-cyclic monophosphate response element binding protein (CREB) are messenger molecules that play important roles in neuronal plasticity and survival. This study was undertaken to examine the effects of acute ethanol on ERK, PKB, and CREB activation in the brain. Methods: Immunoblot analysis was used to determine the effects of a 1-hr exposure of ethanol on levels of phospho-ERC in primary cortical cultures and in the cerebral cortex, hippocampus, and cerebellum of postnatal day 5 (PN5), postnatal day 21 (PN21), and adult rats. Results: In cortical cultures, ethanol (100 mM) significantly reduced activity-dependent activation of phospho-ERK, phospho-PKB, and phospho-CREB by approximately 50%. In PN5 rats, ethanol (3.5 g/kg) inhibited both phospho-ERK and phospho-PKB in the cerebral cortex and hippocampus but was without effect in the cerebellum. A similar brain region,specific inhibition of phospho-ERK was observed in PN21 rats, whereas in adult rats, ethanol inhibited phospho-ERK in all three brain regions. In contrast, ethanol had no effect on phospho-PKB in either PN21 or adult rats. Without exception, ethanol inhibited phospho-CREB in an identical brain region, and age-dependent manner as was observed for phospho-ERK. Finally, administration of the NMDA antagonist MK-801 (0.5 mg/kg) to PN5 rats had no effect on phospho-ERK or phospho-PKB levels in any brain region. Conclusion: The results demonstrate that acute ethanol inhibits ERK/PKB/CREB signaling in brain. This inhibition occurs in an age- and brain region,specific manner, with inhibition of PKB restricted to a time during the brain growth-spurt period. Furthermore, the lack of effect of MK-801 suggests that inhibition of NMDA receptors is unlikely to play a major role in binge ethanol inhibition of ERK/PKB/CREB signaling in vivo. [source] Cellular Adaptation to Chronic Ethanol Results in Altered Compartmentalization and Function of the Scaffolding Protein RACK1ALCOHOLISM, Issue 10 2003Alicia J. Vagts Background: Previously, we found that acute ethanol induces the translocation of the scaffolding protein RACK1 to the nucleus. Recently, we found that nuclear RACK1 mediates acute ethanol induction of immediate early gene c-fos expression. Alterations in gene expression are thought to lead to long-term changes that ultimately contribute to the development of alcohol addiction and toxicity. Therefore, we sought to determine the effects of chronic exposure of cells to ethanol on the cellular compartmentalization of RACK1 and on c-fos messenger RNA (mRNA) and protein expression. Methods: Rat C6 glioma cells were used as the cell culture model. Immunohistochemistry was implemented to visualize the localization of RACK1 and to monitor the protein level of c-fos. Reverse-transcription polymerase chain reaction was used to measure c- fos mRNA levels. The Tat-protein transduction method was used to transduce recombinant Tat-RACK1 into cells as previously described. Results: Chronic exposure of cells to 200 mM ethanol for 24 and 48 hr resulted in the gradual re-distribution of RACK1 out of the nucleus. It is interesting to note that acute ethanol re-challenge immediately after chronic treatment did not result in RACK1 translocation to the nucleus, and nuclear compartmentalization of RACK1 in response to acute ethanol was detected only after 24 hr of withdrawal. Similar patterns were obtained for c-fos expression. Chronic exposure to ethanol did not result in an increase in mRNA or protein levels of c-fos. Furthermore, acute ethanol exposure did not increase c-fos protein levels in cells that were first treated chronically with ethanol. However, transduction of exogenous RACK1 expressed as a Tat-fusion protein was able to rescue c- fos mRNA expression after chronic ethanol exposure. Conclusions: Our data suggest that RACK1 nuclear compartmentalization and ethanol-induced c-fos expression are transient and are desensitized to ethanol during prolonged exposure to high concentrations. The desensitization is temporary, and RACK1 can respond to acute ethanol treatment after a 24-hr withdrawal period. Our data further suggest that the altered compartmentalization of RACK1 leads to differences in c-fos expression upon acute or chronic exposure to ethanol. In summary, RACK1 is an important molecular mediator of the acute and chronic actions of ethanol on the expression of c-fos. These findings could have implications for the molecular signaling pathways leading to pathologic states associated with alcoholism, including toxicity. [source] |