PARP inhibition in vivo blocks alcohol-induced brain neurodegeneration and neuroinflammatory cytosolic phospholipase A2 elevations

Chronic alcoholism promotes brain damage that impairs memory and cognition. High binge alcohol levels in adult rats also cause substantial neurodamage to memory-linked regions, notably, the hippocampus (HC) and entorhinal cortex (ECX). Concurrent with neurodegeneration, alcohol elevates poly (ADP-ribose) polymerase-1 (PARP-1) and cytosolic phospholipase A2 (cPLA2) levels. PARP-1 triggers necrosis when excessively activated, while cPLA2 liberates neuroinflammatory ω-6 arachidonic acid. Inhibitors of PARP exert in vitro neuroprotection while suppressing cPLA2 elevations in alcohol-treated HC-ECX slice cultures. Here, we examined in vivo neuroprotection and cPLA2 suppression by the PARP inhibitor, veliparib, in a recognized adult rat model of alcohol-binging. Adult male rats received Vanilla Ensure containing alcohol (ethanol, 7.1 ± 0.3 g/kg/day), or control (dextrose) ± veliparib (25 mg/kg/day), by gavage 3x daily for 4 days. Rats were sacrificed on the morning after the final binge. HC and ECX neurodegeneration was assessed in fixed sections by Fluoro-Jade B (FJB) staining. Dorsal HC, ventral HC, and ECX cPLA2 levels were quantified by immunoblotting. Like other studies using this model, alcohol binges elevated FJB staining in the HC (dentate gyrus) and ECX, indicating neurodegeneration. Veliparib co-treatment significantly reduced dentate gyrus and ECX neurodegeneration by 79% and 66%, respectively. Alcohol binges increased cPLA2 in the ventral HC by 34% and ECX by 72%, which veliparib co-treatment largely prevented. Dorsal HC cPLA2 levels remained unaffected by alcohol binges, consistent with negligible FJB staining in this brain region. These in vivo results support an emerging key role for PARP in binge alcohol-induced neurodegeneration and cPLA2-related neuroinflammation.

Alcohol Teratogenesis: Mechanisms of Damage and Strategies for Intervention

There are multiple mechanisms by which alcohol can damage the developing brain, but the type of damage induced will depend on the amount and developmental timing of exposure, along with other maternal and genetic factors. This article reviews current perspectives on how ethanol can produce neuroteratogenic effects by its interactions with molecular regulators of brain development. The current evidence suggests that alcohol produces many of its damaging effects by exerting specific actions on molecules that regulate key developmental processes (e.g., L1 cell adhesion molecule, alcohol dehydrogenase, catalase), interfering with the early development of midline serotonergic neurons and disrupting their regulatory-signaling function for other target brain structures, interfering with trophic factors that regulate neurogenesis and cell survival, or inducing excessive cell death via oxidative stress or activation of caspase-3 proteases. The current understanding of pathogenesis mechanisms suggests several strategic approaches to develop rational molecular prevention. However, the development of behavioral and biologic treatments for alcohol-affected children is crucial because it is unlikely that effective delivery of preventative interventions can realistically be achieved in ways to prevent prenatal damage in at-risk pregnancies. Toward that end, behavioral training that promotes experience-dependent neuroplasticity has been effective in a rat model of cerebellar damage induced by alcohol exposure during the period of brain development that is comparable to that of the human third trimester.

Protective Effects of Tetramethylpyrazine on Cerebrovascular Regulations in Rats with Chronic Alcoholic Encephalopathy

Recent studies showed that pathology of alcoholic encephalopathy was associated with cerebral vascular damage. TMP (tetramethyl- pyrazine) is widely used in the treatment of cerebrovascular diseases, however, it has not been reported whether TMP can relieve alcohol-induced cerebral vascular damages. The study was performed to investigate the learning and memory, cerebrovascular pathological changes and the expressions of vascular endothelial growth factor (VEGF) and serum levelsofendothelin-1 (ET-1) in the rat model of chronic alcoholic encephalopathy, and explore the effects of TMP intervention on alcoholic encephalopathy. In the present study, the rat model of chronic alcoholic encephalopathy was established by the gavage administration of alcohol; the learning and memory ability was tested by Morris water maze; the expression of VEGF was measured by RT-PCR and Western blot; and the serum levels of ET-1 was measured by radioimmunoassay. We found that alcohol intoxication impaired learning and memory, induced VEGF overexpression and increased ET 1 concentrations. TMP intervention improved learning abilities, increased the VEGF expression and reduced ET-1 level. These results indicate that TMP exhibits therapeutic effects on chronic alcoholic encephalopathy.

Impact of thiamine supplementation in the reversal of ethanol induced toxicity in rats

One of the molecular mechanisms of alcohol induced toxicities is mediated by oxidative stress. Hence our studies were focused on the effect of thiamine (antioxidant) in the reversal of alcohol induced toxicity and comparison of the reversal with abstinence. Administration of ethanol at a dose of 4 g/kg body wt/day for 90 days to Sprague Dawley rats manifested chronic alcohol induced toxicity evidenced by decreased body weight, an increase in liver-body weight ratio, increase in activities of serum and liver aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (GGT); decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase in the liver and brain. The levels of inflammatory markers, fibrosis markers and DNA fragmentation were also elevated in the serum, liver and brain. After ethanol administration for 90 days, the reversal of the alcohol induced toxicity was studied by supplementing thiamine at a dose of 25 mg/100 g body wt/day. Duration of the reversal study was 30 days. The activities of AST, ALT, GGT, scavenging enzymes as well as markers of inflammation and fibrosis in serum, liver and brain were reversed to a certain extent by thiamine. Changes in neurotransmitter levels in brain were also reversed by thiamine supplementation. DNA damage was decreased and DNA content increased in thiamine supplemented group compared to abstinence group showing a faster regeneration. In short, histopathological and biochemical evaluations indicate that thiamine supplemented abstinent rats made a faster recovery of hepatic and neuronal damage than in the abstinence group.

[Features of psychopharmacotherapeutic correction of alcohol dependence in the elderly]

The article is devoted to the actual in modern medicine problem as the study of the prevalence of alcohol dependence and its psyhofarmacological correction in the elderly. It is shown that elderly and old age as a result of reduction of the reserve capacity of the organism for clinical pathology becomes addictive specific psychopathological features that affect the course of disease and maintenance of preventive treatment. On the basis of empirical evidence the authors prove that at the border severity of alcohol withdrawal syndrome the drug "Cytoflavin" has a fairly pronounced psyhofarmacological activity for older people with alcohol dependence.

The nociceptin/orphanin FQ system as a target for treating alcoholism

Nociceptin (known also as orphanin FQ) is the most recently discovered member of the endogenous opioid peptide family, albeit nearly 15 years ago. Nociceptin renders or influences many behavioral, psychological and neurobiological processes, including memory, anxiety, stress and reward. Since its discovery, results of a steady stream of studies have suggested that endogenous nociceptin might be involved in responses to addictive drugs, and that targeting the nociceptin system may be beneficial in treating addictions. The current review summarizes and critically appraises those studies, particularly those that point to an application in treating alcoholism. Overall, most, studies suggest that the endogenous nociceptin system has a physiological role in mediating or regulating behavioral responses to alcohol, and that activating nociceptin receptors suppresses ongoing alcohol consumption or reinstatement of responding for alcohol. These findings encourage the development of therapies targeted at the nociceptin system for the treatment of alcoholism in humans, though a minor number of studies showing continuous activation of the nociceptin receptor can produce increased, rather than reduced, alcohol consumption emphasize the necessity of further investigation.

Antioxidant neuroprotection against ethanol-induced apoptosis in HN2-5 cells

Earlier studies from this and other laboratories show that ethanol induces apoptotic death of fetal and neonatal neurons. One mechanism that underlies these effects is the ethanol-associated reduction in the phosphatidylinositol 3' kinase pro-survival pathway. Another mechanism involves the oxidative stress caused by the ethanol-associated increase in reactive oxygen species (ROS). In the present study, we used the murine HN2-5 hippocampal-derived cell line to investigate the effects of ethanol on ROS levels and apoptosis. We also investigated the potential neuroprotective effects of two structurally unrelated antioxidants: N-acetylcysteine (NAC) and melatonin. The results demonstrate that NAC blocked an ethanol-associated increase in ROS. In addition, NAC and melatonin prevented the augmentation of apoptosis in ethanol-treated neurons. Both antioxidants significantly elevated the expression of the anti-apoptotic gene XIAP in ethanol-treated and/or control neurons and melatonin increased Bcl-2 expression in ethanol-treated neurons. Thus, it is possible that the neuroprotective effects of NAC and melatonin involve their ability to augment the expression of one or more anti-apoptotic gene as well as their classical antioxidant actions. Additional studies are needed to establish the effectiveness of these antioxidants to prevent the loss of neurons which accompanies in utero exposure to ethanol.

Systematic review of interventions for children with Fetal Alcohol Spectrum Disorders

BACKGROUND

Children with Fetal Alcohol Spectrum Disorders (FASD) may have significant neurobehavioural problems persisting into adulthood. Early diagnosis may decrease the risk of adverse life outcomes. However, little is known about effective interventions for children with FASD. Our aim is to conduct a systematic review of the literature to identify and evaluate the evidence for pharmacological and non-pharmacological interventions for children with FASD.

METHODS

We did an electronic search of the Cochrane Library, MEDLINE, EMBASE, PsychINFO, CINAHL and ERIC for clinical studies (Randomized controlled trials (RCT), quasi RCT, controlled trials and pre- and post-intervention studies) which evaluated pharmacological, behavioural, speech therapy, occupational therapy, physiotherapy, psychosocial and educational interventions and early intervention programs. Participants were aged under 18 years with a diagnosis of a FASD. Selection of studies for inclusion and assessment of study quality was undertaken independently by two reviewers. Meta-analysis was not possible due to diversity in the interventions and outcome measures.

RESULTS

Twelve studies met the inclusion criteria. Methodological weaknesses were common, including small sample sizes; inadequate study design and short term follow up. Pharmacological interventions, evaluated in two studies (both RCT) showed some benefit from stimulant medications. Educational and learning strategies (three RCT) were evaluated in seven studies. There was some evidence to suggest that virtual reality training, cognitive control therapy, language and literacy therapy, mathematics intervention and rehearsal training for memory may be beneficial strategies. Three studies evaluating social communication and behavioural strategies (two RCT) suggested that social skills training may improve social skills and behaviour at home and Attention Process Training may improve attention.

CONCLUSION

There is limited good quality evidence for specific interventions for managing FASD, however seven randomized controlled trials that address specific functional deficits of children with FASD are underway or recently completed.

The role of 5-HT3 receptors in drug abuse and as a target for pharmacotherapy

Alcohol and drug abuse continue to be a major public health problem in the United States and other industrialized nations. Extensive preclinical research indicates the mesolimbic dopamine (DA) pathway and associated regions mediate the rewarding and reinforcing effects of drugs of abuse and natural rewards, such as food and sex. The serotonergic (5-HT) system, in concert with others neurotransmitter systems, plays a key role in modulating neuronal systems within the mesolimbic pathway. A substantial portion of this modulation is mediated by activity at the 5-HT3 receptor. The 5-HT3 receptor is unique among the 5-HT receptors in that it directly gates an ion channel inducing rapid depolarization that, in turn, causes the release of neurotransmitters and/or peptides. Preclinical findings indicate that antagonism of the 5-HT3 receptor in the ventral tegmental area, nucleus accumbens or amygdala reduces alcohol self-administration and/or alcohol-associated effects. Less is known about the effects of 5-HT3 receptor activity on the self-administration of other drugs of abuse or their associated effects. Clinical findings parallel the preclinical findings such that antagonism of the 5-HT3 receptor reduces alcohol consumption and some of its subjective effects. This review provides an overview of the structure, function, and pharmacology of 5-HT3 receptors, the role of these receptors in regulating DA neurotransmission in mesolimbic brain areas, and discusses data from animal and human studies implicating 5-HT3 receptors as targets for the development of new pharmacological agents to treat addictions.

Flumazenil selectively prevents the increase in alpha(4)-subunit gene expression and an associated change in GABA(A) receptor function induced by ethanol withdrawal

The actions of ethanol on gamma-aminobutyric acid type A (GABA(A)) receptors are still highly controversial issues but it appears that some of its pharmacological effects may depend on receptor subunit composition. Prolonged ethanol exposure produces tolerance and dependence and its withdrawal alters GABA(A) receptor subunit gene expression and function. Whereas benzodiazepines are clinically effective in ameliorating ethanol withdrawal symptoms, work in our laboratory showed that benzodiazepines also prevent, in vitro, some of the ethanol withdrawal-induced molecular and functional changes of the GABA(A) receptors. In the present work, we investigated the effects, on such changes, of the benzodiazepine receptor antagonist flumazenil that can positively modulate alpha(4)-containing receptors. We here report that flumazenil prevented both the ethanol withdrawal-induced up-regulation of the alpha(4)-subunit and the increase in its own modulatory action. In contrast, flumazenil did not inhibit ethanol withdrawal-induced decrease in alpha(1)- and delta-subunit expression as well as the corresponding decrease in the modulatory action on GABA(A) receptor function of both the alpha(1)-selective ligand zaleplon and the delta-containing receptor preferentially acting steroid allopregnanolone. These observations are the first molecular and functional evidence that show a selective inhibition by flumazenil of the up-regulation of alpha(4)-subunit expression elicited by ethanol withdrawal.

Postnatal aniracetam treatment improves prenatal ethanol induced attenuation of AMPA receptor-mediated synaptic transmission

Aniracetam is a nootropic compound and an allosteric modulator of AMPA receptors (AMPARs) which mediate synaptic mechanisms of learning and memory. Here we analyzed impairments in AMPAR-mediated synaptic transmission caused by moderate prenatal ethanol exposure and investigated the effects of postnatal aniracetam treatment on these abnormalities. Pregnant Sprague-Dawley rats were gavaged with ethanol or isocaloric sucrose throughout pregnancy, and subsequently the offspring were treated with aniracetam on postnatal days (PND) 18 to 27. Hippocampal slices prepared from these pups on PND 28 to 34 were used for the whole-cell patch-clamp recordings of AMPAR-mediated spontaneous and miniature excitatory postsynaptic currents in CA1 pyramidal cells. Our results indicate that moderate ethanol exposure during pregnancy results in impaired hippocampal AMPAR-mediated neurotransmission, and critically timed aniracetam treatment can abrogate this deficiency. These results highlight the possibility that aniracetam treatment can restore synaptic transmission and ameliorate cognitive deficits associated with the fetal alcohol syndrome.

The CB1 cannabinoid receptor antagonist rimonabant chronically prevents the nicotine-induced relapse to alcohol

Preclinical and clinical research shows that the cannabinoid brain receptor type 1 (CB(1)) modulates alcohol- and nicotine-related behaviors. Throughout the nicotine-induced relapse to alcohol, the rats were pre-treated for 10 days with the CB(1) cannabinoid receptor antagonist rimonabant (0, 0.03, 0.3 and 3.0 mg/kg i.p.). In this condition, a long-lasting nicotine-induced relapse to alcohol was observed, and this effect was reversed in a dose-dependent manner with rimonabant. Surprisingly, rats that were not exposed to nicotine developed tolerance to the effects of rimonabant from the sixth day. Also, 3.0 mg/kg of rimonabant reduced the responses for sucrose. Evaluation in the Elevated Plus-Maze after nicotine treatment did not reveal anxiogenic effects. Finally, at the conclusion of rimonabant treatment, a rapid reinstatement of alcohol consumption was detected. These results suggest that rimonabant can prevent the relapse to alcohol, even when an interaction with nicotine exists-the most frequent situation in human alcohol abuse.

Grape seed flavanols, but not Port wine, prevent ethanol-induced neuronal lipofuscin formation

Lipofuscin is an end-product of lipid peroxidation which dramatically increases following ethanol consumption, as we have shown in hippocampal and cerebellar neurons. In this work, we corroborated observations indicating that supplementation of ethanol with 200 mg/l of grape seed flavanols prevents increased lipofuscin formation, an action that has been ascribed to the antioxidant properties of the flavanols. Because wine is an alcoholic beverage naturally rich in flavanols, we decided to study the effect of chronic ingestion of Port wine (PW), which also contains 20% ethanol and approximately 200 mg/l of flavanol oligomers, upon lipofuscin accumulation in the hippocampal CA1 and CA3 pyramidal neurons and in the cerebellar Purkinje cells. Six months old rats were fed with PW and results were compared with those obtained in ethanol-treated groups and pair-fed controls. After 6 months of treatment, the volume of lipofuscin per neuron was estimated using unbiased stereological methods. Treatment with PW resulted in an increase of lipofuscin in all neuronal populations studied when compared to controls and to rats treated with ethanol supplemented with flavanols. No differences were observed when comparisons were made with ethanol drinking rats. We conclude that PW, despite containing 20% ethanol and flavanols, does not prevent ethanol-induced lipofuscin formation as previously found in animals drinking ethanol plus flavanols. The reduced antioxidant capacity of PW might depend on the type and amount of flavanols present and on its content in sugars.

Alcohol abuse in the critically ill patient

Alcohol abuse and dependence disorders are common in the 10% of hospitalised patients who need admission to the intensive care unit (ICU), but these disorders are often undiagnosed. The systemic effects from the excessive use of alcohol increase susceptibility to, or directly cause various important disorders in the critically ill. Early recognition of alcohol abuse and dependence is necessary and should prompt consideration of several alcohol-specific diagnoses that have important prognostic and therapeutic implications for these patients. We discuss the use of screening tests to improve the identification of alcohol abuse and dependence disorders, the epidemiology and pathogenesis of important alcohol-related disorders, differences in the presentation of several common alcohol-related diagnoses in the ICU, and important alcohol-specific therapies.

Anticonvulsive effects of kappa-opioid receptor modulation in an animal model of ethanol withdrawal

Although the neurochemical mechanisms contributing to alcohol withdrawal seizures are poorly understood, withdrawal seizures probably reflect neuronal hyperexcitability resulting from adaptation to chronic alcohol. Altered kappa-Opioid receptor (KOP-R) signaling has been observed in multiple seizure types; however, a role for this system in ethanol withdrawal seizures has not been systematically characterized. We hypothesized that pharmacological manipulations of the KOP-R would alter withdrawal in mice selectively bred for differences in ethanol withdrawal severity. Withdrawal Seizure-Prone (WSP) and Withdrawal Seizure-Resistant (WSR) mice were made physically dependent using chronic ethanol vapor inhalation, and the effects of the KOP-R antagonist nor-binaltorphimine or agonist U-50,488H on withdrawal severity were examined. Pretreatment with nor-binaltorphimine significantly increased handling-induced convulsion (HIC) severity in withdrawing WSR mice, with no observable effects in withdrawing WSP mice. In contrast, U-50,488H significantly decreased HIC severity in WSP mice, with no effects in WSR mice. During extended withdrawal (i.e. hours 12+), a rebound hyperexcitability was observed in WSP mice given agonist. Thus, administration of a KOP-R antagonist increased withdrawal severity in mice normally resistant to withdrawal seizures, while a KOP-R agonist reduced convulsion severity in animals susceptible to withdrawal seizures. These observations are consistent with differences in the KOP-R system observed in these lines at the molecular level, and suggest the KOP-R system may be a promising therapeutic target for management of ethanol withdrawal seizures. Finally, these findings underscore the importance of determining the potential for rebound increases in withdrawal severity during later withdrawal episodes.

Glial-derived neurotrophic factor (GDNF) prevents ethanol (EtOH) induced B92 glial cell death by both PI3K/AKT and MEK/ERK signaling pathways

We investigated the neuroprotective effect of glial-derived neurotrophic factor (GDNF) upon alcohol-exposed B92 cultures, as well as the role of the cytoskeleton and mitogen-activated protein kinase (MAPK) pathways in this effect. Ethanol (EtOH) was added to cultures, either alone or in combination with 30 ng/ml GDNF. Exposure to EtOH (86 and 172 mM; 60 and 120 min) increased the frequency of apoptotic cells identified by nuclear DNA staining with 4,6-diamidino-2-phenylindole (DAPI). Cultures treated with GDNF showed a decrease in ethanol-induced apoptosis. A jun N-terminal kinase (JNK) pathway is activated by EtOH and their pharmacological inhibition (by SP600125) neutralized ethanol-induced apoptosis, suggesting a role for JNK in EtOH neurotoxicity. Immunocytochemically detected phospho-JNK (p-JNK) showed an unusual filamental expression, and localized together with actin stress fibers. Examination of the cytoskeleton showed that EtOH depolymerized actin filaments, inducing p-JNK dissociation and translocation to the nucleus, which suggests that released p-JNK may contribute to glial cell death after EtOH exposure. Treatment with GDNF, in turn, may neutralize the ethanol-induced cell death pathway. Either a phosphatidylinositol 3-kinase (PI3K)/AKT pathway inhibitor (LY294002) or an inhibitor of the extracellular signal-regulated kinase (ERK) 1, 2 pathways (UO126) failed to neutralize GDNF protective effects. However, the simultaneous use of both inhibitors blocked the protective effect of GDNF, suggesting a role for both signaling cascades in the GDNF protection. These findings provide further insight into the mechanism involved in ethanol-induced apoptosis and the neurotrophic protection of glial cells.

[Reversible demyelinisation of corpus callosum in the course of Marchiafava-Bignami disease]

Marchiafava-Bignami disease is a rare disorder of an unknown aetiology that is marked by focal demyelinisation in the corpus callosum. Chronic alcohol abuse plays an important role in its development. Its course is unfavourable, although rare cases of clinical improvement confirmed in MRI have been reported. Until now, no case of Marchiafava-Bignami disease diagnosed intra vitam was so far described on the territory of Poland. The authors present such a case with favourable course. A 52-year-old male with chronic alcoholism was hospitalised due to altered consciousness which developed subacutely prior to admission. The first MRI scans yielded demyelinating lesions in the corpus callosum. The clinical and radiological findings were consistent with the diagnosis of Marchiafava-Bignami disease. Thiamine, vitamin B12, folic acid and amantadine were administered, which resulted in an improvement in both motor and cognitive functions. Control MRI scans revealed remyelinisation of the corpus callosum. Hence, this technique proved itself to be useful in monitoring the course of the disease.

[Marchiafava-Bignami disease]

Marchiafava-Bignami disease (MBD) is a rare central nervous system disorder of an unknown etiology strongly associated with alcoholism. MBD primarily affects the corpus callosum leading to confusion, dysarthria, seizures and frequently to death. About 250 cases of different races and nationalities, mostly alcoholics have been reported. We report a single-case study of a 43-year-old woman with the history of severe alcohol abuse, who demonstrated typical picture of Marchiafava-Bignami disease (MBD) with fatal course. We reviewed the literature on cases of MBD.

Changes in the beta-endorphin plasma level after repeated treatment with acamprosate in rats selectively bred for high and low alcohol preference

The aim of this study was to evaluate the beta-endorphin (beta-endorphin) plasma level in Warsaw Low Preferring (WLP) and Warsaw high-preferring (WHP) rats after repeated administration of acamprosate, one of most effective drug in the treatment of alcoholism. Treatment with acamprosate in dose 200mg/kg, p.o. for 10 days induced an increase in plasma beta-endorphin levels. A single injection of ethanol also results in the increase of beta-endorphin level. Moreover, it was found that single injection of ethanol to WHP rats resulted in lower increase of plasma beta-endorphin content in rats earlier treated with acamprosate. In WLP rats, repeated acamprosate treatment prevents the ethanol-induced increase in plasma beta-endorphin level. It may be concluded that acamprosate modulates the endogenous opioid system.

Glycyl-glutamine in nucleus accumbens reduces ethanol intake in alcohol preferring (P) rats

Opioid peptides and glycyl-glutamine (Gly-Gln) have been implicated in the control of ethanol consumption. A recognized beta-endorphin cleavage product, Gly-Gln, inhibits voluntary alcohol consumption when microinjected into the nucleus accumbens (AcbSh) of P rats. To evaluate the site-specific efficacy of Gly-Gln on ethanol consumption following AcbSh application, ethanol preferring (P) rats were allowed to establish individual baseline ethanol/water consumption utilizing a voluntary self-administration paradigm. Subsequent to baseline ethanol consumption being established, bilateral guide cannulae were stereotaxically implanted +1 mm dorsal to the AcbSh for subsequent Gly-Gln (100 nmol/microl) or saline vehicle (1 microl) injections. Alcohol intake, body weight, and water intake were measured at 24 h post-injection intervals. Unilateral Gly-Gln injections reduced ethanol consumption 35.6% (P < 0.05) from pre-established baseline consumption (6.24 +/- 0.64 g/kg to 4.06 +/- 0.28 g/kg). Bilateral Gly-Gln injections further reduced consumption to 51.9% (6.4 +/- 1.0 g/kg to 3.08 +/- 0.65 g/kg at 24 h (P < 0.01) below established baseline values within 24 h without significant changes in body weight or water consumption. Also, the amino acid constituents of the dipeptide had no influence on ethanol consumption behavior; however, Gly-Gln efficacy was shown to be comparable to central beta-endorphin-(1-27) or intraperitoneal (i.p.) naltrexone-induced suppression of ethanol intake. These data indicate that the AcbSh exhibits a site-specific sensitivity to the suppressive actions of Gly-Gln or beta-endorphin-(1-27) injections that modulate voluntary ethanol consumption in P rats. These findings support the broader concept that select forebrain opioid-responsive neural sites may influence the development or expression of alcohol abuse syndromes in animal models or humans.

CPP and amlodipine alter the decrease in basal acetylcholine and choline release by audiogenic stimulus in hippocampus of ethanol-withdrawn rats in vivo

Effects of N-methyl-D-aspartate (NMDA) receptor and Ca2+ channel antagonists on extracellular acetylcholine and choline release in the hippocampus of ethanol-withdrawn rats were investigated by in vivo microdialysis. Ethanol was administered to Wistar rats in a liquid diet for 28 days. Basal acetylcholine and choline levels significantly increased at the 24th hour of ethanol withdrawal syndrome (EWS). Either an NMDA receptor antagonist (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) or a calcium channel antagonist amlodipine was administered, and 15 min later, an audiogenic stimulus (100 dB, 1 min) was applied to rats. While audiogenic stimulus increased acetylcholine and had no effect on choline release in control rats, it decreased acetylcholine and increased choline release in ethanol-withdrawn rats. CPP (15 mg/kg) and amlodipine (20 mg/kg) reversed the decrement in acetylcholine and increment in choline release in EW rats. Their effects on acetylcholine and choline release were not different from saline in control rats. Therefore, our findings suggest that, (a) because of adaptive changes in EWS, decrease of the acetylcholine release following audiogenic stimulus may play a role in the triggering of seizures, (b) hippocampal glutamatergic pathway may play a role in the audiogenic stimulus induced decrement of acetylcholine release in EWS, (c) inhibition of this pathway by NMDA receptor and calcium channel antagonists may prevent triggering of the seizures.

Effects of NMDA glutamate receptor antagonist drugs on the volitional consumption of ethanol by a genetic drinking rat

The ability of drugs that reduce NMDA receptor activity on the volitional consumption of ethanol in the genetic drinking rat, mHEP line, was investigated. After the consumption of ethanol solutions and water by each male or female mHEP rat had stabilized on its preferred concentration, different doses of LY 274614, a competitive NMDA antagonist, MK 801, a non-competitive NMDA antagonist, (+)-HA-966 or ACPC (1-aminocyclopropane-1-carboxylic acid), antagonists of the glycine site were administered daily for three days. The dose of 3.0 mg/kg i.p. LY 274614 reduced the consumption of ethanol by 64% compared to the pre-treatment baseline, while 0.3 mg/kg of MK 801 reduced consumption by 44%, 20 mg/kg (+)-HA-966 reduced consumption by 47% and 300 mg/kg of ACPC reduced consumption by 30%. These doses of LY 274614 and MK 801 reduced the ability of Sprague-Dawley rats to walk on a rotorod. Effects of these drugs on food intake were small except for the 20 mg/kg dose of (+)-HA-966. Therefore, the drugs did not have an anti-caloric effect and manipulations of the glutamatergic system through NMDA receptors may modify the consumption of ethanol. This interaction should be explored further for its therapeutic potential and to better understand the control by central neuronal systems of the consumption of ethanol.

Protective effects of melatonin against ethanol-induced reactive gliosis in hippocampus and cortex of young and aged rats

Evidence has been accumulated indicating that chronic ethanol consumption leads to direct or indirect changes in the viability of central nervous system cells. The effects of aging and chronic ethanol consumption on glial markers [glial fibrillary acidic protein (GFAP) and S100B] and oxidant and antioxidant status of rats were studied. Furthermore, protective effects of melatonin against aging and alcohol consumption were also assayed. Chronic ethanol administration to young and aged rats produced an increase in lipid peroxidation, and a decline in glutathione (GSH) levels, which was significantly reversed by the co-administration of melatonin. Lipid peroxidation status was markedly affected in aged rats treated with alcohol compared to the young rats. An age-related increase in GFAP and S100B levels were found in the cortex and hippocampus. Long-term alcohol exposure resulted in distinct elevation in GFAP content in young rats (P < 0.01) while there was less increase in the cortex of aged rats (P < 0.05). In old rats, hippocampal GFAP levels were not significantly changed by alcohol treatment (P > 0.05). Co-administration of melatonin with alcohol significantly reduced GFAP contents both in the hippocampus (P < 0.01) and cortex (P < 0.001) of aged rats. No significant effects of alcohol treatment were found on the levels of neuron-specific enolase (NSE) in aged rats. This finding suggests that melatonin exerts its protective effect on injured nervous tissues by scavenging free radicals and stabilizing glial activity against the damaging effects of ethanol and aging. Furthermore, this work suggests that the signal to initiate gliosis is mediated, at least indirectly, by free radical formation.

Attenuation of brain derived neurotrophic factor (BDNF) by ethanol and cytoprotective effect of exogenous BDNF against ethanol damage in neuronal cells

Ethanol-induced cell damage was investigated using human neuroblastomas SH-SY5Y cells, which can be differentiated by retinoic acid. With 100 mM or more of ethanol, cytotoxicity was significantly higher in undifferentiated cells than in differentiated cells. Thus, a severer effect of ethanol was observed in undifferentiated cells. In differentiated cells it was shown that the secreted amount of brain derived neurotrophic factor (BDNF) and the cyclic AMP responsive element binding protein (CREB) activity were significantly reduced by ethanol. These effects may be involved in ethanol-induced cell damage in differentiated cells. It was reported that neurotrophic factors have protective effects and that the hippocampus exclusively was damaged by ethanol. Since SH-SY5Y cell is a cell line (a neuronal cell model) and similar cytotoxic effect of ethanol was observed in both SH-SY5Y and primary culture neuronal cells, it will be favorable to use primary culture cells to test a protective effect of BDNF. Exogenous BDNF was shown to have a protective effect against ethanol-induced damage in primary culture neurons from rat hippocampi.

Effects of 4-methylpyrazole on ethanol neurobehavioral toxicity in CD-1 mice

OBJECTIVES

4-Methylpyrazole (4-MP), an alcohol dehydrogenase (ADH) antagonist, is used for the treatment of ethylene glycol and methanol ingestions. However, ethanol is frequently co-ingested by those who ingest these more toxic alcohols. Several in vitro and in vivo studies have shown a decrease in the elimination rate of ethanol after the administration of 4-MP, but none has evaluated the effects of 4-MP administration on the neurobehavioral toxicity of ethanol. This was a study to determine whether ADH blockade with 4-MP prolongs ethanol neurobehavioral toxicity in a murine model.

METHODS

D-1 mice were pretreated with 4-MP, with observation of its effect on ethanol dose-response curves. 4-MP (25 mg/kg) or an equal volume of saline was administered intraperitoneally. Ten minutes later, incremental ethanol doses of 1-5 g/kg were administered intraperitoneally. Pretreated and control groups were composed of ten mice each for each dose of ethanol tested. Outcomes for assessing ethanol neurobehavioral toxicity were successful performance on the rotarod test and presence of the righting reflex, two established and validated outcome measures for ethanol-induced neurobehavioral toxicity in mice.

RESULTS

The dose of ethanol at which 50% of the animals failed a particular outcome test (toxic dose 50 [TD(50)]) was decreased with 4-MP administration for both the rotarod test and the righting reflex. The TD(50) intergroup differences (control vs. 4-MP) were statistically significant at 60, 120, and 180 minutes (p < 0.05).

CONCLUSIONS

Pretreatment with 4-MP significantly prolonged ethanol neurobehavioral toxicity in CD-1 mice, presumably by inhibiting its metabolism by ADH. Further investigation is warranted to evaluate this interaction.

Nerve growth factor prevents cell death and induces hypertrophy of basal forebrain cholinergic neurons in rats withdrawn from prolonged ethanol intake

We have previously reported that the hippocampal cholinergic fiber network is severely damaged in animals withdrawn from ethanol, and that a remarkable recovery in fiber density occurs following hippocampal grafting, a finding that we suggested to be underpinned by the graft production of neurotrophic factors, which are known to be decreased after ethanol exposure. It is widely accepted that nerve growth factor (NGF) signals the neurons of the brain cholinergic system, including those of the medial septum/vertical limb of the diagonal band of Broca (MS/VDB) nuclei, from which the septohippocampal projection arises. Because neurons in these nuclei are vulnerable to ethanol consumption and withdrawal we thought of interest to investigate, in withdrawn rats previously submitted to a prolonged period of ethanol intake, the effects of intraventricular delivery of NGF upon the MS/VDB cholinergic neurons. Stereological methods were applied to estimate neuron numbers and neuronal volumes in choline acetyltransferase (ChAT)-immunostained and Nissl-stained material. We have found that in ethanol-fed rats there was a significant reduction in the total number of Nissl-stained and cholinergic neurons in the MS/VDB, and that the suppression of ethanol intake further decreased neuron numbers. In addition, the somatic size of ChAT-IR neurons was reduced by ethanol intake, and withdrawal further aggravated neuronal atrophy. NGF treatment prevented the withdrawal-associated loss, and induced hypertrophy, of cholinergic neurons. These findings show that exogenous NGF protects the phenotype and prevents the withdrawal-induced degeneration of cholinergic neurons in the MS/VDB. These effects might be due to the trophic action of NGF upon the basal forebrain cholinergic neurons, including the hippocampal fiber network that conveys this neurotrophin retrogradely to the MS/VDB, and/or upon their targets, that is, the hippocampal formation neurons.

Alcohol and withdrawal: from animal research to clinical issues

The withdrawal syndrome in alcohol-dependent patients appears to be a major stressful event whose intensity increases with repetition of detoxifications according to a kindling process. Disturbances in the balance between excitatory and inhibitory neural processes are reflected in a perturbed physical state while disturbances in the balance between positive and negative reinforcements are reflected in a perturbed mood state. Our purpose is to link the different behavioral outcomes occurring during withdrawal with specific biological brain mechanisms from the animal to the human being. Better understanding of the various biological mechanisms underlying withdrawal from alcohol will be the key to design and to apply appropriate pharmaceutical management, together with appropriate therapy aimed at inducing protracted abstinence.

Rivastigmine in the treatment of alcohol-induced persisting dementia

A case of Alcohol-Induced Persisting Dementia (AIPD) in a 62-year-old man is presented. His progress on treatment with the acetylcholinesterase inhibitor, rivastigmine, is followed. The significant improvement observed suggests that AIPD may be a new indication for this class of drug.

Antioxidants and fetal protection against ethanol teratogenicity. I. Review of the experimental data and implications to humans

Ethanol is the most common human teratogen, and heavy drinking during pregnancy can result in serious adverse outcomes to the fetus. The cellular mechanisms by which ethanol induces damage in utero are not well understood, while induction of oxidative stress is believed to be one putative mechanism. Our objective is to review the data of antioxidant effects in experimental models of fetal alcohol syndrome. Prior to the description of the available experimental data, we will briefly review the mechanisms leading to ethanol-induced oxidative stress. Ethanol-induced oxidative damage to the fetus could be attenuated by a variety of antioxidants as was documented in whole animal and tissue culture studies. Experiments, retrieved from the literature search, are described and criticized. Although experimental data are still limited, the application of a treatment strategy that includes antioxidants is justified since antioxidant treatment in human pregnancy for pre-eclampsia was demonstrated to be safe and effective. The available experimental evidence and the safety of vitamins C and E in pregnancy suggest that experimental use of antioxidants in alcohol-consuming mothers should be seriously considered to reduce fetal alcohol damage.

Resistance to alcohol withdrawal-induced behaviour in Fyn transgenic mice and its reversal by ifenprodil

Recent studies suggest that the protein tyrosine kinase Fyn constitutes a determinant of fear and anxiety as well as alcohol sensitivity in mice. We investigated these functions and their relatedness in mice with transgenic over-expression of native or mutated, constitutively active Fyn. Fear- and anxiety-related behaviour of these animals were normal under varying levels of stress, but under withdrawal from alcohol both types of transgenic mice failed to show any increase of anxiety-like behaviour or reduction of exploratory activity as seen in their wild-type littermates. This apparent lack of alcohol withdrawal-induced behavioural effects was associated with increased Fyn activity and tyrosine phosphorylation of several proteins including the NMDA receptor subunit NR2B in the different mutant lines. NR2B phosphorylation itself remained unaffected by the chronic alcohol ingestion and subsequent withdrawal, but challenge with an NR2B antagonist, ifenprodil, restored a normal behavioural response in alcohol-withdrawn fyn mutants. Moreover, both types of transgenic mice showed a reduction of voluntary alcohol consumption compared to their wild-type littermates. Together, these results suggest that Fyn can modulate alcohol consumption and prevent behavioural changes during alcohol withdrawal, possibly via phosphorylation of NR2B.

Alpha-lipoic acid prevents ethanol-induced protein oxidation in mouse hippocampal HT22 cells

Oxidative stress is involved in a number of neurological disorders, including the neurotoxic effects of ethanol. Recent studies have described a neuroprotective potential of alpha-lipoic acid (LC) in several models of neuronal cell death related to oxidative stress. We tested the hypothesis that LC could be effective in preventing ethanol-induced neurotoxicity employing the clonal hippocampa cell line HT22. A 24 h incubation with ethanol 100-600 mM caused a dose-dependent loss of cell viability and a significant increase of the overall intracellular protein oxidation. Coincubation with LC 0.1 mM resulted in a significant decrease of ethanol-related neurotoxicity and a complete prevention of the ethanol-induced intracellular protein oxidation. These results indicate that the radical scavenging properties of LC are effective to ameliorate ethanol-induced neurotoxicity.

5-HT(1A) receptor antagonist p-MPPI attenuates acute ethanol effects in mice and rats

The effect of a selective 5-HT(1A) antagonist, 4-(2'-methoxy-)phenyl-1-[2'-(N-2"-pyridinyl)-p-iodobenzamino-]ethyl-piperazine (p-MPPI), on acute ethanol-induced hypothermia, sleep and suppression of acoustic startle reflex in C3H/He mice and Wistar rats was studied. Administration of p-MPPI at the doses of 0.4, 0.7 and 1.0 mg/kg reduced in a dose-dependent manner the ethanol-induced hypothermia and the sleep time and attenuated the ethanol-induced decrease of acoustic startle reflex magnitude in mice. Similar p-MPPI (0.4 mg/kg) effects on ethanol-induced sleep and hypothermia were obtained in rats. It was concluded that 5-HT(1A) receptors were involved in the mechanisms of the ethanol-induced hypothermia and sleep, and that 5-HT(1A) antagonist increased acute ethanol tolerance.

Memantine, but not dizocilpine, ameliorates cognitive deficits in adult rats withdrawn from chronic ingestion of alcohol

Adult rats were given a 20% ethanol solution as their only source of fluid for 6 months and then withdrawn from alcohol. During the first 4 weeks of the withdrawal period, animals were intraperitoneally injected with either memantine (20 mg/kg bolus followed by 1 mg/kg every 12 h) or dizocilpine (MK-801; 0.1 mg/kg every 12 h), both of which are antagonists of N-methyl-D-aspartate receptors. Ten weeks after initiation of the withdrawal procedure, cognitive status of animals was assessed using the Morris water maze. Withdrawal from alcohol produced robust deficits in the performance of rats on the acquisition task and on the probe trial. Treatment with memantine resulted in a complete reversal of these behavioral impairments. In contrast, treatment with MK-801 was found to be ineffective in preventing cognitive alterations associated with chronic alcohol consumption and withdrawal.

Can nootropic drugs be effective against the impact of ethanol teratogenicity on cognitive performance?

Rats exposed pre- (PA) and postnatally (PNA) to ethanol at a dose of 1 g/kg for 24 h developed fetal alcohol effects (FAE). This was measured using a condition-reflex method for active avoidance with punishment reinforcement (shuttle-box) in which pronounced learning and memory deficits in 3-month-old rats were found after ethanol exposure (Vaglenova and Petkov, 1998. Fetal alcohol effects in rats exposed pre- and postnatally to a low dose of ethanol. Alcohol. Clin. Exp. Res. 22(3), 697--703). In the present study the effects of piracetam (Pyramem) at a dose of 600 mg/kg body weight, aniracetam at 50 mg/kg, and meclophenoxate (Centrophenoxine) at 100 mg/kg were studied. The drugs were administered orally during 10 days to separate groups of naive and pre- and postnatally exposed to ethanol rats. All the investigated nootropic drugs showed a significant possibility to alleviate learning and memory disability of rats with FAE. Aniracetam was administered to 1-month-old rats, demonstrating a prolonged (2 months) therapeutic effect, observed in rats aged 3 months. As previously reported (Vaglenova and Petkov, 1998), between male rats with FAE and controls, 66 and 33% were 'poor learners', respectively. In all nootropic treatment groups the percentage of 'poor learners' dropped to 28%. The positive effects of piracetam, aniracetam and meclophenoxate suggest that these drugs could be used for both treatment and prophylactic of FAE-connected disturbances of cognition.

Transfection of C6 glioma cells with glia maturation factor upregulates brain-derived neurotrophic factor and nerve growth factor: trophic effects and protection against ethanol toxicity in cerebellar granule cells

Glial cells play active roles in neuronal survival, as well as neuroprotection against toxic insult. Recent studies suggest that the brain protein glia maturation factor (GMF) is involved in intracellular signaling in glia. This study investigated whether or not GMF plays a role in the survival-promoting and neuroprotective functions of glia. C6 glioma cells were transfected in vitro with GMF utilizing an adenovirus vector. The transfected cells overexpressed GMF intracellularly, but did not secrete the protein. The conditioned medium (CM) was obtained from the GMF-transfected cells (CM-GMF) and tested on primary neuronal cultures, consisting of cerebellar granule cells (CGC). The CGC cultures were utilized because these cultures have a background level of cell death, and the survival-promoting, i.e. neurotrophic effect, of the CM could be tested. In addition, since CGC cultures are ethanol-sensitive (ethanol enhances neuronal death), the neuroprotective effect of the CM against ethanol-induced cell death was tested also. We demonstrated that the CM-GMF had an enhanced neurotrophic effect as well as an increased neuroprotective effect against ethanol-induced cell death compared to control CM obtained from untransfected C6 cells (CM-Mock) or CM obtained from cells transfected with an unrelated gene (CM-LacZ). Because neurotrophins have trophic and protective effects, we investigated whether GMF-transfection upregulated the expression of neurotrophins in C6 cells. RT-PCR verified that GMF-transfected C6 cells had increased mRNA levels for BDNF and NGF. Immunoblotting corroborated the RT-PCR results and indicated that CM-GMF contained greater concentrations of BDNF and NGF protein compared to CM-Mock and CM-LacZ. A soluble TrkB-IgG fusion protein, which selectively binds BDNF and prevents its binding to the neuronal TrkB receptor, eliminated the neurotrophic effect of CM-GMF; whereas anti-NGF antibody was ineffective in preventing this effect, suggesting that the neurotrophic effect was due to BDNF. On the other hand, both the TrkB-IgG fusion protein and anti-NGF reduced neuroprotection, suggesting that BDNF and NGF both contribute to the neuroprotective effect of CM-GMF. In conclusion, GMF upregulates the expression of BDNF and NGF in C6 cells, and these factors exert neurotrophic and neuroprotective functions on primary neurons.

Differential effects of a dihydropyridine calcium channel antagonist on the components of ethanol tolerance

The dihydropyridine calcium channel antagonist, nimodipine, was found to decrease the extent of tolerance that developed to the ataxic action of ethanol in experimental designs in which the tolerance was not context-specific, when ethanol was given by liquid diet. When ethanol was given by injection, so that cues were present for the effects of ethanol during the chronic treatment, tolerance to the ataxic actions of ethanol was unaffected. Nimodipine, however, decreased the tolerance to the hypothermic actions of ethanol, when the ethanol was given by injection. When the rats were given practice sessions on the motor task while under the influence of the ethanol, during the chronic treatment, nimodipine did not affect tolerance to the ataxic actions of ethanol. When nimodipine was given before the motor task learning and ethanol after the practice sessions, the tolerance to the ataxic effect of ethanol was increased. A similar schedule of drug treatment with the NMDA antagonist CGP37849 given before the practice sessions, and ethanol afterwards, resulted in decreased tolerance to ethanol. It is suggested that these changes in ethanol tolerance may be explained by dual actions of nimodipine in, firstly, decreasing the form of tolerance to ethanol that is not dependent on contextual cues and, secondarily, in increasing the learning of a motor task.