Strain and sex differences in repeated ethanol treatment-induced motor activity in quasi-congenic mice

The B6.C quasi-congenic Recombinant QTL Introgression (RQI) strains of the b4i5 series have similar genetic background, but differ in about 5% of their genome from the C57BL/6ByJ (B6) background strain because they carry short chromosome segments introgressed from the BALB/cJ (C) donor strain. These RQI strains were derived from mouse lines selectively bred for high activity of mesencephalic tyrosine hydroxylase (TH/MES), therefore genetic variation in dopamine system-related behaviours, such as ethanol-induced motor activity, can be expected. Males and females of 17 RQI and two progenitor strains were tested for initial motor activity for 15 min after a habituating injection of saline, which was followed by an i.p. injection of saline or ethanol (2 g/kg) and an additional test of motor activity for 30 min. This procedure was repeated during 4 subsequent days. In all strains, the first-day ethanol treatment showed an inhibitory effect. With repetition of the treatment the inhibitory effect decreased, and a stimulatory effect could be observed with significant strain- and sex-dependent variation. Females exhibited higher activity in the saline group than males, and reached an equilibrium of inhibition and stimulation sooner than males with repetition of the ethanol treatment. The highest (> 25-fold) difference in activity after repeated ethanol treatment was detected between females of the two strains B6.Cb4i5-Alpha4/Vad and B6.Cb4i5-Beta13/Vad. These results firstly suggest that females are more sensitive to repeated ethanol exposure than males, secondly they support the observations that ethanol has both inhibitory and stimulatory effects on motor activity, which are affected by sex, genotype, and repetition of treatment, and thirdly offer new quasi-congenic animal models with highly different responses to ethanol allowing one to more quickly move to gene detection.     

Comparison of free and immobilized Pichia pastoris cells for conversion of ethanol to acetaldehyde

Free and immobilized cells of Pichia pastoris were used to convert ethanol to acetaldehyde in small-scale batch reactors. Immobilized cells were less active than free cells (V(max) free = 7.81 g/L h, V(max) immobilized = 3.17 g/L h) due to a number of factors including end product inhibition and diffusional limitations. Immobilized cells were more resistant to heat denaturation both in the presence and absence of ethanol. Immobilized cells retained more of their activity during repeated batch cycles than did free cells.     

Enzymes for acetaldehyde and ethanol formation in legume nodules

Soybean (Glycine max L. var. Wilkin) nodules contain acetaldehyde and ethanol. The cytosol of soybean and other legume nodules contains pyruvic decarboxylase (EC 4.1.1.1) and alcohol dehydrogenase (EC 1.1.1.1). Some of the properties of these enzymes from soybean nodules are described. Their presence indicates that in the microaerobic nodule cytosol some carbohydrate is metabolized by fermentative pathways like those in the roots of flood-tolerant plants.     

Alcohol and acetaldehyde in rat's milk following ethanol administration

Alcohol and acetaldehyde were measured in milk and peripheral blood in chronic alcoholic rats, at 5 and 15 days of lactation. Ethanol in blood increased throughout lactation and the levels of acetaldehyde were much higher than in nonlactating alcoholic rats. The concentration of acetaldehyde in milk was always ca. 50% of that in blood, whereas that of ethanol varied within the range of 44-80% of the blood levels. Blood alcohol levels in the corresponding sucking pups were much lower than in maternal blood and increased throughout lactation. The time course of ethanol and acetaldehyde concentration in blood and milk were determined in normal lactating rats after cyanamide (40 mg/kg) and ethanol administration (2 or 4 g/kg). Milk alcohol reached higher concentrations than in blood within the first hour of ethanol administration, decreasing and remaining constant thereafter at ca. 65% of those in blood. Acetaldehyde levels in milk were always 35-45% lower than in blood. No alcohol dehydrogenase activity was found in homogenates of mammary tissue; however there was some aldehyde dehydrogenase activity. A significant decrease in mammary tissue aldehyde dehydrogenase was found in chronic alcoholic rats. The role of this enzyme is discussed.     

Production of acetaldehyde from ethanol byCandida utilis

Summary Ethanol-adaptedCandida utilis efficiently converted ethanol to acetaldehyde, a chemical feedstock of recognized importance. Acetaldehyde which has a low boiling point (21°C) readily evaporates and is easily recovered, thus this bioconversion could provide an energy saving process for efficient recovery of a useful product from low concentrations of ethanol.     

Artifactual production and recovery of acetaldehyde from ethanol in urine

Ethanol (1575 mg/L) incubated with fresh urine from healthy, ethanol-free subjects yields acetaldehyde. The concentration of acetaldehyde depends upon temperature, time of incubation, and pH. In samples made hypertonic with sodium chloride (200 mg/mL) and in samples filtered through 0.45-micron membranes, acetaldehyde production was not decreased. L-Ascorbic acid (0.1 mg/mL) added to normal pooled urine caused a threefold increase in acetaldehyde production but thiourea (7.6 mg/mL) stopped it. This suggests that the oxidation of ethanol to acetaldehyde is catalyzed by the semidehydroascorbate peroxy radical of ascorbic acid. Recovery of acetaldehyde added to urine was less than 100% over the pH range 1.5 to 10. Relative to blood, artifactual production of acetaldehyde from ethanol in urine is more easily controlled and is up to an order of magnitude less but corrections for the variables above are still required.     

Infusions of acetaldehyde into the arcuate nucleus of the hypothalamus induce motor activity in rats

AimsThe hypothalamic arcuate nucleus (ARH) is one of the brain regions with the highest levels of catalase expression. Acetaldehyde, metabolized from ethanol in the CNS through the actions of catalase, has a role in the behavioral effects observed after ethanol administration. In previous studies acetaldehyde injected in the lateral ventricles or in the substantia nigra reticulata (SNR) mimicked the behavioral stimulant effects of centrally administered ethanol.Main methodsIn the present study we assessed the effects of acetaldehyde administered either into the ARH into a dorsal control or into the third ventricle on locomotion and rearing observed in 30 min sessions in an open field.Key findingsAcetaldehyde injected into the ARH induced horizontal locomotion and rearing for 20 min. In contrast, administration of acetaldehyde into a control site dorsal to the ARH did not have any effect on locomotion. Although acetaldehyde administration into the third ventricle also induced locomotion, the time course for the effect in this area was different from the time course following ARH injections. Acetaldehyde in the ARH produced a long lasting induction of locomotion, while with intraventricular injections the effects disappeared after 5 min.SignificanceThe present results are consistent with previous studies demonstrating that acetaldehyde is an active metabolite of ethanol, which can have locomotor stimulant properties when administered in the ventricular system of the brain or into specific brain nuclei. Some brain nuclei rich in catalase (i.e.; SNR and ARH) could be mediating some of the locomotor stimulant effects of ethanol through its conversion to acetaldehyde.     

Effects of ethanol and acetaldehyde on rat embryos developing in vitro

Summary Rat embryos were explanted on Days 9.5 or 10 of gestation and cultured for 48 to 30h, respectively, in rat serum containing 0, 3, 6, 9 mg/ml of Ethanol (Eth); 0, 10, 20 μg/ml of Acetaldehyde (Ach); 3 mg/ml Eth + 10 μg/ml Ach. At the end of the culture period the embryos were evaluated for vitality, and scored. Some of them were also examined histologically. Embryos exposed to Eth from Day 9.5 showed a dose-related growth retardation associated with a high frequency of malformations (open neural tube, heart defects, branchial arch hypoplasia). The exposure of 9.5-day embryos to 20 μg/ml Ach resulted in 100% embryolethality, whereas 10 μg/ml induced growth retardation and teratogenic effects. When 10-day embryos were exposed to 3 mg/ml Eth or 10 μl/ml Ach no effects were observed, but the highest levels of Eth produced a moderate growth retardation and morphologic defects. Exposure to 20 μg/ml Ach induced hypoplasia of the first arch, but did not alter the score value. The histologic examination of these embryos revealed severe lesions at the level of the neuroepithelium and of the branchial mesenchyma. Similar effects were observed in embryos exposed simultaneously to 3 mg/ml Eth and 10 μg/ml Ach. These results should make us reevaluate the role of Ach in the Eth-induced embryopathies.     

Inhibition of acetaminophen activation by ethanol and acetaldehyde in liver microsomes

Mechanisms of the inhibitory effect of ethanol on acetaminophen hepatotoxicity are controversial. We studied the effects of ethanol and acetaldehyde, an oxidative metabolite of ethanol, on NADPH-dependent acetaminophen-glutathione conjugate production in liver microsomes. Ethanol at concentrations as low as 2mM prevented the conjugate production noncompetitively. Acetaldehyde also inhibited acetaminophen-glutathione conjugate production at concentrations as low as 0.1mM that is comparable with those observed in vivo after social drinking. Acetaldehyde may be involved in ethanol-induced inhibition of acetaminophen hepatotoxicity.     

Lipoprotein-X in hyperlipemic rat serum in chronic ethanol and acetaldehyde administration

The levels of lipoprotein-X in circulation increased with chronic administration of ethanol or acetaldehyde. A similar profile was seen in rat serum with alkaline phosphatase activity and bilirubin content. Total cholesterol, phospholipids and triglyceride contents increased followed by a decrease by progressive feeding with ethanol or acetaldehyde. The effect of acetaldehyde was more pronounced than that of ethanol.     

System of ethanol and acetaldehyde metabolism in the rat liver during the development of ethanol tolerance

Following daily intraperitoneal injections of ethanol at a dose of 3.5 g/kg rats developed tolerance to its hypnotic action, which was manifested in a drastic decrease of ethanol--induced sleep time and the number of animals sleeping more than 60 min. In the liver, this process was characterized by an elevated alcohol dehydrogenase activity and a decreased aldehyde dehydrogenase one, whereas that of MEOS remained unchanged.     

Enzymatic conversion of ethanol into acetaldehyde in a gas-solid bioreactor

Summary The enzymatic conversion of ethanol into acetaldehyde using dried whole cells ofHansenula polymorpha was tried in a gas-solid bioreactor. The bioreactor could be maintained stably over one month at 35°C with complete conversion in the water content under 8% without any serious problems.     

Bioelectronic sniffers for ethanol and acetaldehyde in breath air after drinking

Two kinds of bioelectronic gas sensors (bio-sniffer) incorporating alcohol oxidase (AOD) and aldehyde dehydrogenase (ALDH) were developed for the convenient analysis of ethanol and acetaldehyde in expired gas, respectively. The sniffer devices for gaseous ethanol and acetaldehyde were constructed by immobilizing enzyme on electrodes covered with filter paper and hydrophilic PTFE membrane, respectively. The AOD and ALDH sniffers were used in the gas phase to measure ethanol vapor from 1.0 to 500 ppm, and acetaldehyde from 0.11 to 10 ppm covering the concentration range encountered in breath after alcohol consumption. Both bio-sniffers displayed good gas selectivity which was attributed to the substrate specificity of the relevant enzymes (AOD and ALDH) as gas recognition material. From the results of physiological application, the bio-sniffers could monitor the concentration changes in breath ethanol and acetaldehyde after drinking. The ethanol and acetaldehyde concentrations in expired air from ALDH2 [-] (aldehyde dehydrogenase type 2 negative) subjects were higher than that of the ALDH2 [+] (positive) subjects. The results indicated that the lower activity of ALDH2 induced an adverse effect on ethanol metabolism, leading to ethanol and acetaldehyde remaining in the human body, even human expired air.     

Release of acid proteolytic activity from lysosomes and degradation of protein in organs of rats intoxicated with ethanol and acetaldehyde

Intoxication with ethanol and acetaldehyde resulted in a marked increase of the acid proteolytic activity in the post-lysosomal supernatant of rat kidney, lung, and liver, while the content of protein and acid-soluble tyrosine remained practically unchanged. Proteins of the post-lysosomal supernatant were degraded in vitro by the endogenous proteinase(s) of lysosomal origin at pH 3.5 and 5.5 but not at pH 7.0.     

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity in mice is enhanced by ethanol or acetaldehyde

Persistent neurochemical changes consistent with parkinsonism have been reported in brains of mice treated with repeated high doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We now report that ethanol or acetaldehyde potentiate MPTP-induced damage to mouse striatum. One hour after the combined treatments (ethanol and MPTP or acetaldehyde and MPTP), the animals exhibited a marked and long-lasting catatonic posture and then returned gradually to apparently normal locomotion. Seven days after MPTP administration, depletion of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in mouse striatum were further potentiated in the group of animals treated with ethanol. This effect was more evident when the treatment was repeated twice and was dose-dependent. Acetaldehyde was more potent than ethanol in enhancing MPTP neurotoxicity. A single exposure to acetaldehyde before and during MPTP treatment produced a very consistent fall of DA, DOPAC and HVA but not serotonin (5HT) or 5-hydroxyindoleacetic acid (5HIAA) in the striatum. This suggests that ethanol effects on MPTP neurotoxicity might be related to acetaldehyde formation.