Blood Ethanol Elimination Rate Research Articles

Purinergic modulation of ethanol-induced sleep time in long-sleep and short-sleep mice

The long-sleep (LS) and short-sleep (SS) mice were selectively bred for differences in sensitivity to the depressant effects of ethanol. In addition to their differential sensitivity to ethanol, they are also differentially sensitive to purinergic agonists and antagonists. This suggests that there may be differences in the purinergic systems of these lines of mice which may aid in understanding how they differ in ethanol sensitivity. We have investigated whether these drugs are capable of modifying acute ethanol sensitivity as measured by ethanol-induced loss of the righting response (ethanol sleep time), waking blood and brain ethanol concentrations, and blood ethanol elimination rate. The purinergic agonists cyclohexyladenosine (CHA), L-phenylisopropyladenosine (PIA), 2-chloroadenosine (CAD), and N-ethylcarboxamidoadenosine (NEC) increased sleep time in both LS and SS mice, however, LS mice were generally more affected than SS. The LS and SS mice were also differentially sensitive to the purinergic antagonists, theophylline and caffeine. Blood and brain ethanol concentration on awakening suggested that CNS sensitivity to acute ethanol administration was altered by pretreatment with agonists but not antagonists. Two agonists, CHA and NEC, significantly lowered ethanol elimination in both lines of mice while PIA, CAD, and the antagonists theophylline, and caffeine were without affect on elimination rate. These data support previous observations that adenosine-mediated systems may be involved in the modulation of ethanol sensitivity.

LS X SS recombinant inbred strains of mice: initial characterization.

In order to assess the genetic correlates of differences in ethanol-induced anesthesia, a set of 27 recombinant inbred (RI) strains was derived from an initial cross of the "long-sleep" (LS) and "short-sleep" (SS) selected lines of mice. In generations F24 and F25, samples of 534 and 580 mice from the LSXSS RI strains were tested for fall time, sleep time, and blood ethanol at awakening subsequent to intraperitoneal injection of a 4.1-g/kg body weight dose of ethanol. Approximately 2 weeks later, mice from F24 were also tested for body temperature lowering and blood-ethanol elimination rate (beta 60). Differences among the average ethanol-induced sleep-time scores of the RI strains are large (ranging from 36 to 171 min) and account for over 50% of the observed variance. Effects due to generation, sex, litters within strains, and the interaction between strain and generation are also significant, but account for relatively small proportions of the total variance. Quantitative genetic analyses of these data suggest that differences in sleep-time scores are polygenic; however, allelic differences at the albino (c) locus may have a pleiotropic effect. Genetic correlations between sleep time and blood ethanol at awakening (-0.79) and between body temperature 60 min after injection and beta 60 (+0.48) are significant. Because differences among the LSXSS RI strains are large and highly reliable, they should be valuable animal models for testing more searching hypotheses about the etiology of individual differences in ethanol-induced anesthesia.

Dietary manipulation of ethanol preference in the Syrian Golden hamster

Male Golden Syrian hamsters, in which ethanol preference was previously established, were fed a basal diet supplemented with essential fatty acid-rich oils (increased weekly from 10–160 g/kg diet), cholesterol (10 g/kg diet) or retinol palmitate (100 or 200 mg/kg diet), each in an independent study. Within 4–5 weeks, all three supplements were associated with significantly decreased ethanol preference. No consistent change in the fatty acid composition of liver or brain was associated with the decrease in ethanol preference but, in ethanol-fed hamsters, each of the supplements was associated with an increase in total cholesterol and the cholesterol/phospholipid ratio in liver. The essential fatty acid-induced reduction in ethanol preference was not associated with a significant change in blood ethanol elimination rate or time.

Ethanol metabolism in vivo by the microsomal ethanol-oxidizing system in deermice lacking alcohol dehydrogenase (ADH)

To assess the importance of non-ADH ethanol metabolism, ADH-negative and ADH-positive deermice were fed liquid diets containing ethanol or isocaloric carbohydrate for 2–4 weeks. Blood ethanol disappearance rate increased significantly after chronic ethanol feeding in both strains. Although at low ethanol concentrations (between 5 and 10 mM) there was no significant difference between ethanol-fed and pair-fed control animals, at high ethanol concentrations (between 40 and 70 mM) blood ethanol elimination rates were increased significantly after chronic ethanol feeding in both ADH-positive and ADH-negative animals. There was no significant effect of the catalase inhibitor 3-amino-l, 2, 4-triazole on the ethanol elimination rates in both strains. Whereas catalase and ADH activities were not altered after chronic ethanol treatment, the activity of the microsomal ethanol-oxidizing system (MEOS) was enhanced three to four times in both strains, and microsomal cytochrome P-450 content was also increased significantly. When MEOS activity was expressed per cytochrome P-450 content, it was higher in ADH-negative than in ADH-positive animals, and it increased after ethanol administration. When microsomal proteins were separated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, ethanol-fed animals had a distinct band which reflected the increase in microsomal cytochrome P-450 content and seemed to reflect a unique form of cytochrome P-450 induced by ethanol. Thus, despite the absence of the ADH pathway, a large amount of ethanol was metabolized by MEOS in ADH-negative deermice; this was associated with increased blood ethanol elimination rates, enhanced MEOS activity, and quantitative and qualitative changes of cytochrome P-450.

Estimated lethal ethanol concentrations in relation to age, aspiration, and drugs.

In 98 deaths certified to be due to accidental alcohol poisoning, maximum antemortal blood ethanol concentrations were estimated as the sum of postmortal concentration and the product of blood ethanol elimination rate (0.258 g/liter/hr) and the time interval between the discontinuation of drinking and death. The estimated mean maximum concentration (g/liter) was 4.63 for uncomplicated cases, 4.26 for cases with heart disease, 3.98 for cases in which aspiration of stomach contents had contributed to death, 3.59 for ethanol-barbiturate poisonings, and 3.11 for combinations of ethanol and other psychotropic drugs. The mean for this last group was significantly lower than that for the first or the second group (p less than .001). The mean concentration for ethanol-barbiturate poisonings was signicantly lower than the mean for the uncomplicated cases (p = .01). In the two first groups combined, the higher the age, the lower the ethanol concentration (r = -.27; p = .02). Likewise, the postmortal blood ethanol concentration correlated negatively with age (r = -.26; p = .02), after controlling for the time interval. The lethal ethanol concentration for the aged seems to be lower than that for young people. A possible explanation for this phenomenon is the loss of ethanol tolerance.

Ethanol elimination rates in mice: Effects of gender, nutrition, and chronic ethanol treatment

Twenty male and 20 female mice of a heterogeneous stock were assigned to each of three groups. One group was administered ethanol in a liquid diet for 9 days, a second group was fed an isocalorically controlled diet containing no ethanol for the same length of time, and the third group was fed standard lab chow. Each animal was injected with a dose of ethanol equal to 3.5 g/kg body weight at the time corresponding to 6 hr post-withdrawal for the ethanol-treated group. Blood ethanol elimination rates were determined at 1, 2, and 3 hr post-injection. Neither gender, nutritional state, nor chronic ethanol treatment was found to affect ethanol elimination rates.

Decreased in vivo acetaldehyde oxidation and hepatic aldehyde dehydrogenase inhibition in C57BL and DBA mice treated with carbon tetrachloride

Male C57BL 6J (C57) and DBA 2J (DBA) mice were dosed with 500 μl/kg ig CCl 4, 24 hr before a 3.25 g/kg ip dose of ethanol. The relative bioavailability of CCl 4 was similar in both mouse strains. CCl 4 pretreatment produced genotypically related decreases in blood ethanol elimination rates with DBA mice showing the greater decrease. Blood acetaldehyde concentrations were significantly elevated in the CCl 4-pretreated animals of both strains. DBA CCl 4-pretreated mice exhibited significantly higher blood acetaldehyde concentrations than C57 mice 1, 2, 3, and 4 hr after ethanol administration. CCl 4 pretreatment resulted in acetaldehyde elevations of approximately threefold in C57 mice four- to fivefold in DBA mice. Four hours after the ethanol dose, animals were sacrificed for enzymatic analyses of hepatic aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) activity. The specific activities and activity per gram of cytosolic and mitochondrial ALDH were decreased in both mouse strains. ADH activity was not significantly altered by CCl 4 pretreatment. Liver necrosis, as measured by serum alanine aminotransferase activity, was similar in both strains (approx fivefold increase). These data indicate that CCl 4 increased blood acetaldehyde concentrations by inhibiting hepatic cytosolic and mitochondrial ALDH and that the degree of blood acetaldehyde elevation is different in the two inbred mouse strains C57 and DBA.

Ethanol metabolism in Peromyscus genetically deficient in alcohol dehydrogenase

Ethanol metabolism was compared in two strains of the deermouse, Peromyscus maniculatus. Animals of the Adh N/ Adh N strain, which lack liver alcohol dehydrogenase (ADH) activity, eliminated ethanol at a signficantly slower rate (P < 0.0005) than those of the Adh F/ Adh Fstrain, which have normal liver ADH activity. However, a comparison of the blood ethanol elimination rate (BEER) in the two strains indicated that, at high blood ethanol concentrations, non-ADH mediated pathways may account for as much as two-thirds of normal ethanol elimination in this species. Chronic ethanol consumption induced an elevated BEER in Adh F/ Adh F mice but not in AdhN/ Adh N mice. This strain difference in response to ethanol feeding suggests that increases in BEER are mediated primarily via the ADH pathway. A microsomal ethanol-oxidizing system (MEOS), independent of ADH and catalase, was shown to exist in microsomal preparations from both strains of P. maniculatus. MEOS activity of naive Adh N/ Adh N mice was 2.3-fold higher than that of naive Adh F/ Adh H animals. Both strains had a 3-fold greater MEOS activity following chronic ethanol consumption. Contrary to similar investigations in ethanol-fed rats, the alteration in MEOS activity was not accompanied by significant changes in cytochrome P-450, NADPH-cytochrome c reductase or phospholipid. Most importantly, the elevated in vitro MEOS activity of ethanol-fed Adh N/ Adh N mice had no significant effect upon BEER. These results suggest caution in attaching physiological significance to the simultaneous, ethanol-induced increase of the in vitro MEOS and of BEER in experimental animals with normal liver ADH activities.

Free-choice ethanol intake and ethanol metabolism in the hamster and rat

Hamsters, as previously reported, demonstrated greater ethanol intake and preference than rats. However, as ethanol was gradually added to a sweet solution, hamster ethanol intakes did not consistently exceed ethanol metabolic capacity for prolonged periods. In ethanol-naive hamsters and rats, alcohol dehydrogenase activities and ethanol metabolic rates of isolated hepatocytes in vitro and blood ethanol elimination rates in vivo show consistent large interspecific differences corresponding to the species' differences in ethanol intake and preference. The data suggest a limiting role of ethanol metabolism in the regulation of maximized free-selection ethanol intake by rodents, and provide an explanation for the absence of continuously elevated blood ethanol levels and alcohol withdrawal syndrome in hamsters during periods of comparatively high daily ethanol intake.

Alcohol metabolism in man: Effect of intravenous fructose infusion on blood ethanol elimination rate following stimulation by phenobarbital treatment or chronic alcohol consumption

The effect of phenobarbital (PB) pretreatment and of chronic alcoholism on blood ethanol elimination rate (BEER) was investigated in man. In order to gain additional information concerning the mechanism of possible changes BEER was determined before and during intravenous infusion of fructose, a compound known to increase the NADH-oxidizing capacity of the liver and thereby stimulating alcohol oxidation rate. Following PB-treatment (300 mg/day for 5-6 days, n = 8) a marked increase in unstimulated (U-) BEER was obtained. But the fructose stimulated (FS-) BEER was not significantly changed by PB-treatment. In chronic alcoholics (n = 15) U-BEER values above the upper limit (chi + 2 S D) obtained in healthy controls, were observed only when the time of sobriety was less than one week (n = 6). Values of FS-BEER in chronic alcoholics with increased basal alcohol oxidation rates were in the same range as those of healthy controls. In 5 out of the 6 alcoholics in whom the values were elevated on admission, BEER decreased significantly after withdrawal of alcohol for 2-4 weeks. Since FS-BEER was nearly identical in all conditions tested, the distinct changes in U-BEER are probably independent of changes in the activity of enzymes involved in alcohol oxidation. It is assumed that alcohol metabolism in man is mainly controlled by the rate of NADH reoxidation in the liver.

Role of the malate—aspartate shuttle in the metabolism of ethanol in vivo

In order to assess the role of the malate-aspartate shuttle during ethanol oxidation in vivo, the influence of aminooxyacetate administration was investigated on both the blood ethanol elimination rate and ethanol induced alterations of the liver redox state. Aminooxyacetate reduced by 50 per cent the blood ethanol elimination rate; it promoted at the same time the reduced state of the extramitochondrial space, whereas it induced a more oxidized state in the mitochondria. The comparison between the effect of either single or repeated administration of aminooxyacetate leads to the conclusion that the degree of inhibition of aspartate aminotransferase activity and the reduction of blood ethanol elimination rate are not directly connected. These findings suggest that an increased flux through other shuttle systems concerned with transport of reducing equivalents occurs when the malate-aspartate shuttle is inhibited.