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Abstract— The enzymes catalysing ethanol metabolism, alcohol dehydrogenase (EC 1.l.1.1) and aldehyde dehydrogenase (EC 1.2.1.3), were assayed in a variety of neural and somatic tissues of the rat, the human counterparts of which are known to be vulnerable to excessive ethanol. The activity of alcohol dehydrogenase was assayed by the coupled oxidation of ethanol and reduction of lactaldehyde, a method which we have recently found to be sufficiently sensitive and specific to measure the relatively low levels of activity in whole brain. Detectable activities of these enzymes were found in peripheral nerve, skeletal muscle, retina, optic nerve and various regions of brain, as well as in a variety of non‐neural tissues. The levels of the enzymic activities in all tissues were markedly lower than those of liver, but probably sufficient to perform a local function in the metabolism of ethanol or other endogenous substrates. The activity of alcohol dehydrogenase in the various tissues, like that of liver, was confined to the cytosol and exhibited kinetic properties and responses to inhibitors almost identical to those of the liver enzyme. We consider the results to be consistent with the hypothesis that the pathological effects of alcohol may be related, at least in part, to local mechanisms for the metabolism of alcohol.

Abstract— The activities of 7 enzymes (hexokinase, phosphofructokinase, glucose‐6‐P dehydrogenase, 6‐P‐gluconic dehydrogenase, NADP linked isocitric dehydrogenase, malic dehydrogenase and lactic dehydrogenase) were measured in individual nerve cell bodies of 8 different neuronal types: pyramidal cells from cerebral cortex and Amnion's horn, Purkinje cells, giant cells in the reticular formation, Deiters’nucleus cells, facial nucleus cells, anterior horn cells and dorsal root ganglion cells. Samples of similar size were analysed from the molecular layer of cerebellum.The cell bodies were dissected from frozen‐dried tissue sections and weighed on quartz fibre balances. The weights ranged from 0–2 ng for the smallest pyramidal cells to 9 ng for the largest giant cells. The specific enzymatic reactions were carried out in small volumes (0–01–5 μl) under mineral oil (‘oil‐well technique’). The NADPH2 or NAD formed was amplified by‘enzymatic cycling’and measured fluorometrically. A new cycling method was used for measuring the NAD formed in three of the enzymatic methods. Double cycling was used to measure glucose‐6‐P and 6‐P‐gluconate dehydrogenases in the smallest cell bodies.Each type of neuron exhibited a unique enzyme pattern, but four general patterns could be distinguished. The most variable of the enzymes was glucose‐6‐P dehydrogenase which was nearly 10‐fold higher in anterior horn cells than in pyramidal cells from the cerebral cortex. Malic dehydrogenase was the most constant, with a 3‐fold range from the highest (Purkinje cells) to the lowest (dorsal root ganglion cells).

Abstract— Effects of the acute and chronic administration of ethanol have been investigated in mouse brain on the redox‐state, citric acid cycle function, levels of adenine nucleotides and other metabolites. Cerebral oxidation of ethanol, activity of alcohol dehydrogenase and the permeability of brain and liver mitochondrial preparations after chronic ethanol administration have been also investigated. Acute or chronic administration of ethanol resulted in a small but significant increase in the reduced components of certain dehydrogenase‐linked substrate pairs in brain. Pyrazole, an inhibitor of alcohol dehydrogenase, prevented the ethanol‐induced changes in brain. 14CO2 production from several substrates was inhibited in brains from chronically ethanol‐fed animals. Addition of pyrazole, however, prevented the ethanol‐mediated inhibition of 14CO2 production. Chronic administration of ethanol resulted in decreased levels of ATP and creatine phosphate in the brain, and increased contents of ADP and AMP. The cerebral activities of alcohol dehydrogenase and succinic dehydrogenase, oxidation of ethanol, mitochondrial oxidation of a‐glycerophosphate, and levels of NADH remained unaffected by the chronic administration of ethanol. In contrast to liver, where chronic administration of ethanol increased the contribution of 'substrate shuttles’resulting in increased oxidation of ethanol; in brain, the contribution of these 'shuttles’remained unaffected.

Abstract:The steady‐state brain/plasma distribution ratios of [14C]deoxyglucose ([14C]DG) for hypoglycemic rats previously determined by measurement of DG concentrations in neutralized acid extracts of freeze‐blown brain and plasma exceeded those predicted by simulations of kinetics of the DG model. Overestimation of the true size of the precursor pool of [14C]DG for transport and phosphorylation could arise from sequestration of [14C]DG within brain compartments and/or instability of metabolites of [14C] DG and regeneration of free [14C]DG during the experimental period or extraction procedure. In the present study, the concentrations of [14C]DG and glucose were compared in samples of rat brain and plasma extracted in parallel with perchloric acid or 65% ethanol containing phosphate‐buffered saline. The concentrations of both hexoses in acid extracts of brain were higher than those in ethanol, whereas hexose contents of plasma were not dependent on the extraction procedure. The magnitude of overestimation of DG content (about 1.2 to fourfold) varied with glucose level and was highest in extracts isolated from hypoglycemic rats; contamination of the [14C]DG fraction with 14C‐labeled nonacidic metabolites also contributed to this overestimation. Glucose concentrations in acid extracts of brain exceeded those of the ethanol extracts by < 40% for normal and hypoglycemic rats.

AbstractThis study involved mice that received 4 days of ethanol (EtOH) vapor inhalation and then were assessed for type 1 inositol 1,4,5‐trisphosphate receptor (IP3Rs‐1) expression and the development of EtOH‐induced place preference at various time points in withdrawal.IP3R‐1 protein was found to be significantly increased in the nucleus accumbens (NAcc) of mice immediately after 4‐day EtOHvapor inhalation, while it significantly reduced to the control level during the next 3 days of withdrawal from EtOHinhalation. EtOH(2 g/kg, i.p.)‐induced place preference after 3 days of withdrawal from EtOHvapor inhalation increased dose dependently for 4 days, which was significantly inhibited by 2‐aminophenoxyethane‐borate, an antagonist forIP3Rs. EtOHconditioning significantly increased, compared to alcohol‐naïve control mice, bothIP3R‐1 protein and the release of dopamine in theNAcc of mice after 3 days of withdrawal from EtOHvapor inhaled for 4 days, and this increase ofIP3R‐1 protein was completely abolished by intracerebroventricular injection ofFK506, an inhibitor for calcineurin. These results indicate that the sensitization of EtOH‐induced place preference is due to up‐regulatedIP3R‐1 via calcineurin‐mediated pathway after enhanced release of dopamine in theNAcc on EtOHadministration during EtOHconditioning.imageWe revealed signal transduction pathways that may promote sensitization of ethanol (EtOH)‐induced place preference. EtOH facilitated the release of dopamine (DA) in the Nucleus accumbens (NAcc), enhancing calcineurin function via dopamine D1‐like and D2‐like receptor activation, which in turn resulted in increased NFATc4 expression. Increase in NFATc4 may further facilitate transcription factor binding to IP3R‐1 promoter domain to stimulate IP3R‐1 synthesis. Such increased IP3R‐1 elevates intracellular Ca2+concentration via facilitated mobilization of Ca2+from the intracellular Ca2+stores to the cytosol.

Abstract— Chronic ethanol ingestion in rats leads to a slow rise in brain alcohol dehydrogenase activity which levels off after 2 weeks at approximately twice the initial activity. The half‐time of the rise is approximately 8 days. Abrupt withdrawal of the ethanol is followed by a rapid decline of the brain alcohol dehydrogenase activity to the normal level with a half‐time of approximately 15 h. The difference in time constants between the rise in enzyme activity during ethanol‐feeding and its decline following withdrawal suggests that the increased enzyme activity is at least in part the result of a reduced rate constant of enzyme degradation in the presence of ethanol. The effect of ethanol on brain alcohol dehydrogenase activity is not altered by supplementation of the diet with carbohydrate or vitamins. The effect is seen only in the cerebral hemispheres and not in the brain‐stem. Acquisition of tolerance to ethanol during chronic ethanol ingestion and its extinction following withdrawal follow almost the same time courses as the changes in brain alcohol dehydrogenase activity.

AbstractAlcohol engages signaling pathways in the brain. Midkine (MDK) is a neurotrophic factor that is over‐expressed in the prefrontal cortex of alcoholics.MDKand one of its receptors, anaplastic lymphoma kinase (ALK), also regulate behavioral responses to ethanol in mice. The goal of this study was to determine whetherMDKandALKexpression and signaling are activated by ethanol. We found that ethanol treatment of neuroblastoma cells increasedMDKandALKexpression. We also assessed activation ofALKby ethanol in cells and found thatALKandALK‐dependent extracellular signal‐regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3) phosphorylation increased rapidly with ethanol exposure. Similarly, treatment of cells with recombinantMDKprotein increasedALK,ERKand STAT3 phosphorylation, suggesting that ethanol may utilizeMDKto activateALKsignaling. In support of this, transfection of cells withMDKsiRNAs attenuatedALKsignaling in response to ethanol. Ethanol also activatesERKsignaling in the brain. We found that inhibition ofALKor knockout ofMDKattenuated ethanol‐inducedERKphosphorylation in mouse amygdala. These results demonstrate that ethanol engagesMDKandALKsignaling, which has important consequences for alcohol‐induced neurotoxicity and the regulation of behaviors related to alcohol abuse.imageWe propose that ethanol (a) increases transcription of the anaplastic lymphoma kinase (ALK) and midkine (MDK) genes and (b) rapidly activates extracellular signal‐regulated kinase (pERK1/2) and signal transducer and activator of transcription 3 (pSTAT3) through MDK and ALK. Activation of ALK and MDK signaling by ethanol may alter behavioral responses to ethanol with implications for the development of alcohol use disorders.

Abstract: Repeated amphetamine administration to rats under chronic ethanol intoxication resulted in the formation of 1,3‐dimethyl‐1,2,3,4‐tetrahydroisoquinoline (1,3‐DiMeTIQ), a novel metabolite of amphetamines. 1,3‐DiMeTIQ was quantified with a sensitive, specific assay using gas chromatography‐mass spectrometry. It was not found in the brains of rats given repeated amphetamine administration but no ethanol. The chronic ethanol‐intoxicated rats subjected to repeated amphetamine administration exhibited behavioral abnormalities, such as repeated convulsions and curving of the back. 1,3‐DiMeTIQ contents were markedly higher in the brain or plasma of rats manifesting abnormal behavior in comparison with those in rats behaving normally. Thus, the 1,3‐DiMeTIQ content in the rat brain seems to have some relationship with behavioral abnormalities. This study also confirmed that 1,3‐DiMeTIQ can cross the blood‐brain barrier in the rat. Intraperitoneal 1,3‐DiMeTIQ injections to rats caused behavioral symptoms similar to those observed in rats with chronic ethanol intoxication and repeated amphetamine administration. The effect of toxic doses of 1,3‐DiMeTIQ on dopaminergic and serotonergic metabolism in the whole rat brain was also investigated.

Abstract: The effect of acute ethanol administration on histamine (HA) dynamics was examined in the mouse hypothalamus. The steady‐state level of HA did not change after intraperitoneal administration of ethanol (0.5–5 g/kg), whereas the level of tele‐methylhistamine (t‐MH), a predominant metabolite of brain HA, increased when 3 and 5 g/kg of ethanol was given. Pargyline hydrochloride (80 mg/kg, i.p.) increased the level of t‐MH by 72.2% 90 min after the treatment. Ethanol at any dose given did not significantly affect the t‐MH level in the pargyline‐pretreated mice. Decrease in the t‐MH level induced by metoprine (10 mg/kg, i.p.), an inhibitor of HA‐N‐methyltransferase, was suppressed by ethanol (5 g/kg), thereby suggesting inhibition of the elimination of brain t‐MH. Ethanol (5 g/kg) significantly delayed the depletion of HA induced by (S)‐α‐fluoromethylhistidine (50 mg/kg, i.v.), a specific inhibitor of histidine decarboxylase. Therefore, a large dose of ethanol apparently decreases HA turnover in the mouse hypothalamus.