Mean Blood Ethanol Concentration Research Articles

The effect of sample hemolysis on blood ethanol analysis using headspace gas chromatography.

Hemolysis, a common occurrence in blood collected for chemical analysis, has been reported to affect analytical test results for some analytes depending upon the material tested and the analytical technique employed. The potential for hemolysis to impact blood ethanol determinations using headspace gas chromatography of samples diluted with an internal standard was investigated. A sample of non-hemolyzed blood and a matched sample of hemolyzed blood were both analyzed thirty times for ethanol concentration using headspace gas chromatography. The mean ethanol concentration measured for the non-hemolyzed samples was 0.0639g/dl. The mean ethanol concentration measured for the hemolyzed samples was 0.0642g/dl. The calculated t value, 1.897, was less than the critical t value, 2.002, at a 0.05 level of significance. There was no measured statistical difference detected between the mean blood ethanol concentration determined for a hemolyzed whole blood sample and a non-hemolyzed whole blood sample.

Consumption of illegal home-made alcohol in Malawi: A neglected public health threat.

This study assessed the ethanol and methanol contents of homemade spirit (Kachasu) sold in Blantyre, Malawi. The likelihood of ethanol and methanol toxicity, respectively, was determined through Monte Carlo simulations using reported Kachasu intake volumes of 21 consumers and the determined methanol and ethanol contents. Ethanol concentration, in samples from 20 different distillers, ranged from 11 to 55% v/v. Methanol was detected in 10 of the 20 samples (0.01-0.28% v/v). The likely mean ethanol intake of drinkers in Blantyre was found to be 214±93mL per day (90% CI, 68.9-373.4mL), and mean methanol intake was 0.44±0.37mL (90% CI, 0.03-1.17mL). The intake values translated to mean blood ethanol and methanol concentrations of 38±16mg/mL and 0.05±0.04mg/mL, respectively. Therefore, the risk of methanol toxicity was considered as negligible. However, there was a high risk of ethanol toxicity. Since production and selling of Kachasu are already illegal in Malawi, enforcement of regulations should be strengthened to reverse the current situation where Kachasu is being distilled and sold openly even within cities. Consumers should also be sensitized about the likely risks associated with consumption of Kachasu in Malawi so that they can make informed choices.

Neuronal Loss in the Developing Cerebral Cortex of Normal and Bax-Deficient Mice: Effects of Ethanol Exposure

Fetal alcohol spectrum disorder is associated with defects in neuronal generation, migration, and differentiation. The present study tested the hypothesis that ethanol exposure during the period of naturally occurring neuronal death causes a time- and Bax-dependent neuronal loss. Wild-type and Bax knockout mice were given a pair of injections (two hours apart) of ethanol (2.5 g/kg) or saline on postnatal day (P) 4, P7, P10, or P13. Mean blood ethanol concentration was 435 mg/dl one hour after the second injection. The total numbers of neurons in individual layers of somatosensory cortex were stereologically determined in 30-day-old mice and the expressions of active caspase 3 immunopositivity and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) were determined 2–36 h after the first injection. On P30, ethanol caused up to 36% neuronal loss in cortical laminae of wild-type mice. In contrast, no ethanol-induced loss was detected in Bax knockout mice. Ethanol also caused an acute bilaminar (layers II/III and V) increase in caspase 3 immunoexpression and TUNEL in wild-type mice. The changes in the expression of these markers were age- and lamina-dependent. No ethanol-induced expression of caspase 3 or TUNEL was detected in Bax knockout animals. Thus, ethanol-induced death of cortical neurons is Bax-dependent, occurs concurrently in all layers, but does not correspond to lamina- and age-dependent expression of DNA fragmentation. Both ethanol-induced and naturally occurring death of cortical neurons rely on caspase 3-dependent and independent mechanisms.

Intravenous ethanol increases dopamine release in the ventral striatum in humans: PET study using bolus-plus-infusion administration of [(11)C]raclopride.

Ethanol increases the interstitial dopamine (DA) concentration in the nucleus accumbens (NAcc) of experimental animals, but positron emission tomography (PET) studies using the single-bolus protocol of the [(11)C]-raclopride competition paradigm have yielded conflicting results in humans. To resolve disparate previous findings, we utilized the bolus-plus-infusion (B/I) method, allowing both baseline and intervention quantification of [(11)C]raclopride binding during a single 105-minute PET scan, to investigate possible ethanol-induced DA release in nine healthy male subjects. A 25-minute intravenous ethanol (7.6%) infusion, resulting in a 1.3 g/L mean blood ethanol concentration, was administered using masked timing during the PET scan. Automated region-of-interest analysis testing the difference between baseline (40-50 minutes) and intervention (60-85 minutes) revealed an average 12.6% decrease in [(11)C]raclopride binding in the ventral striatum (VST, P=0.003) including the NAcc. In addition, a shorter time interval from the start of ethanol infusion to the first subjective effect was associated with a greater binding potential decrease bilaterally in the VST (r=0.92, P=0.004), and the feeling of pleasure was associated with a decrease in binding potential values in both the caudate nucleus (r=-0.87, P=0.003) and putamen (r=-0.74; P=0.02). These results confirm that ethanol induces rapid DA release in the limbic striatum, which can be reliably estimated using the B/I method in one imaging session.

Chronic Free‐Choice Drinking in Crossed High Alcohol Preferring Mice Leads to Sustained Blood Ethanol Levels and Metabolic Tolerance Without Evidence of Liver Damage

Crossed high alcohol preferring (cHAP) mice were selectively bred from a cross of the HAP1×HAP2 replicate lines, and we demonstrate blood ethanol concentrations (BECs) during free-choice drinking that are reminiscent of those observed in alcohol-dependent humans. Therefore, this line may provide an unprecedented opportunity to learn about the consequences of excessive voluntary ethanol (EtOH) consumption, including metabolic tolerance and liver pathology. Cytochrome p450 2E1 (CYP2E1) induction plays a prominent role in driving both metabolic tolerance and EtOH-induced liver injury. In this report, we sought to characterize cHAP drinking by assessing whether pharmacologically relevant BEC levels are sustained throughout the active portion of the light-dark cycle. Given that cHAP intakes and BECs are similar to those observed in mice given an EtOH liquid diet, we assessed whether free-choice exposure results in metabolic tolerance, hepatic enzyme induction, and hepatic steatosis. In experiment 1, blood samples were taken across the dark portion of a 12:12 light-dark cycle to examine the pattern of EtOH accumulation in these mice. In experiments 1 and 2, mice were injected with EtOH following 3 to 4weeks of access to water or 10% EtOH and water, and blood samples were taken to assess metabolic tolerance. In experiment 3, 24 mice had 4weeks of access to 10% EtOH and water or water alone, followed by necropsy and hepatological assessment. In experiment 1, cHAP mice mean BEC values exceeded 80mg/dl at all sampling points and approached 200mg/dl during the middle of the dark cycle. In experiments 1 and 2, EtOH-exposed mice metabolized EtOH faster than EtOH-naïve mice, demonstrating metabolic tolerance (p<0.05). In experiment 3, EtOH-drinking mice showed greater expression of hepatic CYP2E1 than water controls, consistent with the development of metabolic tolerance (p<0.05). EtOH access altered neither hepatic histology nor levels of alcohol dehydrogenase and aldehyde dehydrogenase. These results demonstrate that excessive intake by cHAP mice results in sustained BECs throughout the active period, leading to the development of metabolic tolerance and evidence of CYP2E1 induction. Together, these results provide additional support for the cHAP mice as a highly translational rodent model of alcoholism.

Pharmacologically relevant intake during chronic, free-choice drinking rhythms in selectively bred high alcohol-preferring mice

Multiple lines of high alcohol-preferring (HAP) mice were selectively bred for their intake of 10% ethanol (v/v) during 24-hour daily access over a 4-week period, with the highest drinking lines exhibiting intakes in excess of 20 g/kg/day. We observed circadian drinking patterns and resulting blood ethanol concentrations (BECs) in the HAP lines. We also compared the drinking rhythms and corresponding BECs of the highest drinking HAP lines to those of the C57BL/6J (B6) inbred strain. Adult male and female crossed HAP (cHAP), HAP replicate lines 1, 2, 3 and B6 mice had free-choice access to 10% ethanol and water for 3 weeks prior to bi-hourly assessments of intake throughout the dark portion of the light-dark cycle. All HAP lines reached and maintained a rate of alcohol intake above the rate at which HAP1 mice metabolize alcohol, and BECs were consistent with this finding. Further, cHAP and HAP1 mice maintained an excessive level of intake throughout the dark portion of the cycle, accumulating mean BEC levels of 261.5 ± 18.09 and 217.9 ± 25.02 mg/dl, respectively. B6 mice drank comparatively modestly, and did not accumulate high BEC levels (53.63 + 8.15 mg/dl). Free-choice drinking demonstrated by the HAP1 and cHAP lines may provide a unique opportunity for modeling the excessive intake that often occurs in alcohol-dependent individuals, and allow for exploration of predisposing factors for excessive consumption, as well as the development of physiological, behavioral and toxicological outcomes following alcohol exposure.

Immunohistochemical expression of fibronectin and C5b-9 in the myocardium in cases of fatal ethanol intoxication

Data from the literature indicate that the pulmonary pressure rises in cases of ethanol intake. We have recently proposed a method for the detection of prevalent right ventricular damage in cases of fatal pulmonary thromboembolism and pulmonary fat embolism. In the present study, we compared the expression of the antibodies against fibronectin and C5b-9 in 19 cases of lethal alcohol intoxications (study group: 5 females, 14 males, mean age 46 years, mean blood ethanol concentration 3.5‰, min. 2.11‰, max. 5.31‰) to a group of 26 cases of fatal pulmonary thromboembolism (PE; group 2: 16 females, 10 males, mean age 56 years). Moreover, a group of 15 cases of hanging (group 3: 5 females, 10 males, mean age 50 years) as well as a group of 18 cases of myocardial infarction (group 4: 5 females, 13 males, mean age 61 years) were investigated as examples of typical cardiac damage due to global hypoxia during agony and ischemic damage, respectively. The results of this study show that fresh cardiac damage can be detected at both ventricles in cases of fatal ethanol intoxication with the antibody against fibronectin. The damage is prevalently localised at the right ventricle (RV), as already observed in cases of acute pulmonary hypertension determining right heart failure. The degree of damage at the RV in cases of ethanol intoxications is lower than the one observed in cases of fatal PE.

Acute Effects of Low Doses of Red Wine on Cardiac Conduction and Repolarization in Young Healthy Subjects

Moderate to high blood concentrations of ethanol have been shown to yield acute changes in cardiac electrophysiological properties, but the effect of low concentrations have never been assessed. The role of concomitant changes in clinical variables or cardiac dimensions is also still unknown. This study aimed at exploring the acute effects of low doses of ethanol, administered as Italian red wine, on conduction, depolarization, and repolarization electrocardiographic (ECG) intervals in a population of healthy subjects. Forty healthy young volunteers drank a low quantity of red wine (5 ml/kg), and an equal volume of fruit juice in separate experiments. Heart rate, P-wave duration, PR interval, QRS duration, QT interval, corrected QT interval, QT dispersion, and corrected QT dispersion were assessed at baseline and after 60 minutes from challenge. Mean blood ethanol concentration after drinking was 0.48 +/- 0.06 g/l. Compared to the control challenge, significant changes after red wine intake were observed in P-wave duration (from 101 +/- 11 to 108 +/- 14 milliseconds, p = 0.0006), PR interval (from 153 +/- 15 to 167 +/- 17 milliseconds, p < 0.0001), QT interval (from 346 +/- 28 to 361 +/- 24 milliseconds, p < 0.0001), and corrected QT interval (from 388 +/- 24 to 402 +/- 30 milliseconds, p = 0.0006). None of these changes showed correlations with modifications in clinical or echocardiographic variables. In multivariate analyses aimed at exploring predictors of ECG changes, none of the variables entered the final models. Low doses of red wine acutely slow cardiac conduction and prolong repolarization in normal individuals. These changes are poorly predictable. The potential arrhythmogenic impact of these effects is worthy of exploration.

Are changes in blood-ethanol concentration during storage analytically significant? Importance of method imprecision

Knowledge about the stability of drugs and metabolites in biological fluids is important information when the analytical results are evaluated and interpreted. This study examines changes in blood-ethanol concentration (BEC) during the storage of specimens for up to 12 months at 4 degrees C. Venous blood samples were taken from drunk drivers in evacuated glass tubes containing sodium fluoride and potassium oxalate as chemical preservatives. The concentrations of ethanol in blood were determined in duplicate by headspace gas chromatography on arrival at the laboratory and again after storage in a refrigerator at 4 degrees C for up to 12 months. The relationship between the standard deviation (SD) of analysis of ethanol at concentration intervals of 0.2 mg/g (BEC) was defined by the linear regression equation SD=0.00243+0.0104 BEC (r=0.99). At a mean BEC of 1.64 mg/g, the SD was 0.019 mg/g which corresponds to a coefficient of variation of 1.1%. The mean decrease in BEC (+/-SD) between first and second analysis was 0.105+/- 0.0686 mg/g (t=19.3, d.f.=158, p<0.001) and the loss of alcohol was positively correlated with the duration (days) of storage (r=0.44, p<0.001), although with large inter-tube variations. A correlation also existed (r=0.23, p<0.01) between the loss of ethanol and the starting BEC. When blood samples (n=49) were opened 17 times to remove aliquots for analysis over 6.5 months, the BEC decreased by 0.217+/-0.054 mg/g compared to a fall of 0.101+/-0.076 mg/g in tubes kept unopened. None of the blood samples showed a significant increase in BEC after storage. To be considered analytically significant, the BEC had to decrease by 0.013 (2.6%), 0.028 (1.9%) and 0.045 mg/g (1.8%), respectively at starting concentrations of 0.5, 1.5 and 2.5 mg/g.

Chronic ethanol exposure alters presynaptic dopamine function in the striatum of monkeys: a preliminary study.

Current evidence suggests that dopamine (DA) neurotransmission plays a crucial role in the positive reinforcing and stimulating actions of ethanol (Grace, 2000; Weiss and Porrino, 2002; Diana et al., 2003). Acutely administered ethanol excites DA neurons in the ventral tegmental area (Brodie et al., 1999) and in the substantia nigra pars compacta (Mereu et al., 1984), thereby elevating DA release in terminal fields like the nucleus accumbens (Imperato and Di Chiara, 1986). While these effects on cell bodies are well documented, presynaptic DA terminals do not appear to be influenced directly by acutely applied reinforcing doses of ethanol (Yim and Gonzales, 2000; Budygin et al., 2001a,b). Although the acute actions of ethanol on DA neuronal activity appear clear, many questions remain about the consequences of long-term voluntary ethanol ingestion on the dynamics of DA release and reuptake (Weiss and Porrino, 2002; Diana et al., 2003). One of the important factors contributing to the uncertainty concerning DA system changes in response to chronic ethanol exposure is the limitation of animal models of alcoholism. Oral ethanol self-administration of high doses over a substantial period of time can be obtained in mice, rats, and monkeys (Grant, 2000). However, macaque monkeys will voluntarily self-administer ethanol for years and are similar to humans in their physiology, neurobiology, and genetic code. Thus, monkey models of ethanol self-administration can provide a more homologous approach to study alcoholism (Vivian et al., 2001). Recently, we developed a novel monkey model of voluntary excessive ethanol drinking (Vivian et al., 2001) that has allowed us to characterize the effects of long-term ethanol exposure on striatal DA dynamics using fast-scan cyclic voltammetry (FSCV) in vitro. Using this model (Vivian et al., 2001), six monkeys were allowed continuous access to ethanol (4% w/v) and water for 22 h/day for 18 months following an induction procedure. Monkeys in this protocol consumed varying amounts of ethanol. Average daily intakes were 1.3, 2.2, 2.8, 3.1, 3.2, and 3.5 g/kg/day, and the group daily average intake was 2.7 g/kg/day. The mean blood ethanol concentration (BEC) of the drinking monkeys over the 12 months prior to sacrifice (total of 344 measurements) was 95.6 mg% with a minimum of 0 and a maximum of 485 mg%. BECs were taken 8 h following the session start ( 6 PM) every fifth day. Control animals were ethanol-naive monkeys previously used as controls in studies of high fat diets and atherosclerosis (n 3) or behavioral studies (n 2). Since the data obtained from the animals exposed to previous experimental manipulations were not different from results obtained in naive monkeys, all of these data were analyzed together. The control and alcohol-drinking monkeys were matched for age, weight, and sex. Necropsies took place during the normal 2-h time-out period just after the monkeys had 22 h of continuous access to ethanol. The animals were initially anesthetized with ketamine (10 mg/kg, i.m.) and maintained at a deep surgical plane of anesthesia with pentobarbital, according to the Animal Care and Use guidelines of Wake Forest University Health Sciences. They were then transcardially perfused with cold modified Kreb’s buffer containing (in mM): NaCl 126, KCl 3, MgCl2 1.5, CaCl2 2.4, NaH2PO4 1.2, glucose 11, NaHCO3 25.9, and saturated with 95% O2 / 5% CO2. Brains were rapidly

Developmental alterations of ethanol sensitivity in selectively bred high and low alcohol sensitive rats

Initial sensitivity and acute tolerance to ethanol have been implicated as risk factors in the development of alcoholism in humans. These behaviors were investigated in rats selectively bred for differences in hypnotic sensitivity following their first dose of ethanol in two different experiments. In Experiment 1, developmental profiles of the association between initial sensitivity and acute tolerance induced by a single exposure to ethanol were examined using male and female high, low, and control alcohol sensitive (HAS, LAS, and CAS) rats. Dose–response curves were constructed for duration of the loss of the righting reflex and for blood ethanol concentration (BEC) at the regain of the righting reflex. Animals were tested with a single ethanol dose ranging from 1.5 to 5.0 g/kg at either 15, 25, 40, 70, 120, or 180 days of age (DOA). For each group, acute tolerance to ethanol was estimated by the slope of the regression line using dose of ethanol and mean BEC at regain. In general, all rat lines showed an increase in hypnotic sensitivity to ethanol with age. To a large degree, the lower sensitivity observed in 15 and 25 DOA HAS and LAS rats was associated with an increase in the development of acute ethanol tolerance relative to older rats. Divergence of the LAS and CAS lines was evident by 25 DOA and remained stable with advancing age. However, HAS rats did not differ significantly from CAS rats until 40 DOA, after which the magnitude of the difference continued to increase with age. In Experiment 2, rats were treated with alcohol at 25, 70, or 180 DOA. Rats at 70 or 180 DOA required less ethanol to disrupt their motor coordination on a rotating dowel (rotarod). Blood ethanol levels were determined at the loss and subsequent regain of the ability to negotiate the rotarod. Total duration of inability to negotiate the rotarod also was recorded. HAS rats were less able to remain on a rotarod while under the influence of alcohol relative to LAS and CAS rats regardless of age. However, no evidence of acute tolerance was observed in this experiment and, in fact, there was evidence of reverse tolerance in that all animals had lower BEC values at regain of ability than they did at loss.

Comparison of Ethanol Metabolism in Male and Female Cynomolgus Macaques (Macaca fascicularis)

The physiological consequences of drinking ethanol differ among men and women; however, the biological basis of this gender difference is unknown. Our study characterized sex-related blood ethanol concentration (BEC) 60 min postethanol administration and ethanol elimination rates in male and female monkeys and across the phases of the menstrual cycle. Subjects were male (n = 4) and female (n = 4) cynomolgus monkeys (Macaca fascicularis) with a history of ethanol exposure and maintained at a lean body weight by food restriction. On three separate occasions, each monkey was administered 1.0 g/kg ethanol intragastrically and blood samples (20 microl) were collected every 60 min over a 5-hr period. For females, three phases of the menstrual cycle were determined by the presence of menses and plasma progesterone levels. There was no effect of menstrual cycle on mean 60 min BECs or mean rates of elimination. Mean BECs 60 min after 1.0 g/kg ethanol were: males = 86 mg/dl (+/- 2; n = 4) and females = 82 mg/dl (+/- 5; n = 4). There was no effect of sex on the highest BEC measured, which occurred at the 60 min time point in all subjects. Female monkeys did have faster average rates of ethanol elimination [34 +/- 2 (mg/dl)/hr] compared with males [23 +/- 1 (mg/dl)/hr]. The sex differences in metabolism of ethanol found with the macaque monkey model correlates well with human subject studies and suggests this is an appropriate model to further explore gender differences in response to ethanol.

National Association of Medical Examiners Pediatric Toxicology (PedTox) Registry Report 3

Data are presented from the National Association of Medical Examiners' (St. Louis, MO, U.S.A.) Pediatric Toxicology (PedTox) Registry. A total of 839 case reports have been submitted to the registry. Reported here are the concentrations of several drugs and potentially toxic substances observed in children who have died of various causes, often non-drug-related. Except for carbon monoxide, for each of the substances addressed in this report, there is insufficient information in the literature to distinguish "lethal" from "non- or sublethal" concentrations in children, and the data are presented only to provide a working frame of reference. For 30 infants whose deaths were attributed to causes other than phenobarbital, the median blood phenobarbital concentration was 7.8 mg/L, with a range of 0.1-22.4 mg/L. For eight infants whose deaths were not attributed to ethanol, the mean blood ethanol concentration was 0.029 gm/dl and ranged from 0.011 gm/dl to 0.050 gm/dl. Blood dextromethorphan concentrations in seven infants showed a mean of 0.38 mg/L and ranged from 0.10 mg/L to 0.95 mg/L. In 15 infants, blood pseudoephedrine concentrations ranged between 0.07 mg/L and 13.0 mg/L, with a mean concentration of 3.55 mg/L. Blood carboxyhemoglobin saturations for 38 children aged < or = 5 years, who died in fires and were dead on the scene and not resuscitated, ranged between 29% and 94%, with a mean saturation of 64%. Blood benzene concentrations in eight children aged < or = 6 years who died in fires and were dead on the scene showed a mean concentration of 2.3 mg/L and a range of 0.2-4.9 mg/L. For 33 children aged < or = 5 years whose deaths were attributed to nondrug causes, the mean blood acetaminophen concentration was 9.9 mg/L, and the range was 1.0-34.5 mg/L. These data are not well controlled in terms of testing methodology or cause of death determinations and should not be used as the sole source of information when assessing whether or not a death is caused by one of these substances. Further data and controlled studies are needed to work toward establishing lethal concentrations of certain drugs and toxic substances in children, and the reporting of cases to the PedTox Registry is encouraged.

POTENTIATION OF THE MITOGENIC EFFECT OF ESTROGEN ON THE PITUITARY-GLAND BY ALCOHOL-CONSUMPTION

The effect of alcohol on estrogen-regulated lactotropic cell proliferation was examined in Fisher 344 rats. Alcohol was administered for 2 weeks using liquid diet containing 8.7% ethanol (v/v) and 37% ethanol-derived calories. The control group was pair-fed with an isocaloric diet minus the ethanol or adlib-fed with normal diet. Ethanol-treated rats showed mean blood ethanol concentrations between 60-90 mg/dl. Alcohol treatment did not effect the body growth rate, but increased the DNA synthesis in lactotropes and reduced the levels of lactotropic growth inhibitory transforming growth factor-beta 1 (TGF-beta 1) protein and mRNA in the pituitary. These results suggest that alcohol promotes estrogen-induced lactotropic proliferation, possibly by down regulating the inhibitory TGF-beta 1 control of lactotropic function.

Nocturnal oxygen saturation in advanced chronic obstructive pulmonary disease after a moderate dose of ethanol

The effect of a moderate oral dose of ethanol/(0.5 g.kg-1 body weight) on nocturnal arterial oxygen saturation (SaO2) was evaluated in nine male patients with advanced chronic obstructive pulmonary disease (COPD), (median forced expiratory volume in one second (FEV1) 0.9 l, arterial oxygen tension (PaO2) 9.3 kPa, arterial carbon dioxide tension (PaCO2) 5.3 kPa). During the four study nights (two after alcohol and two after placebo intake), the patients were monitored by whole-night computerized recordings of SaO2 (Biox-oximeter), airflow (thermistors) and respiratory as well as body movements (static charge sensitive bed). After alcohol intake, the mean blood ethanol concentration (SEM) in the evening was 42(2.3) mg.100 ml-1. Alcohol intake was associated with a marginal deterioration of nocturnal oxygenation; the mean (SEM) nocturnal SaO2 was 88.4(2.0) % after alcohol ingestion and 89.1(1.6) % after placebo ingestion, respectively. Only during the first 2 h in bed was there a statistically significant difference in SaO2 in favour of placebo (p less than 0.05). It is concluded that moderate alcohol intake in the evening, corresponding to "social" drinking, did not substantially aggravate nocturnal oxygenation in our patients with advanced COPD and mild to moderate daytime hypoxaemia.

ALTERATIONS IN SEROTONIN RECEPTOR SUBTYPES IN ETHANOL-DEPENDENT RATS

Serotonin (5-HT) receptor subtypes were investigated during severe ethanol intoxication and withdrawal. Ethanol was administered intragastrically five times a day for 4 days (12 g/kg per day). 5-HT receptor subtypes were studied: (1) in severely intoxicated animals (mean blood ethanol concentration (BEC) = 4.7 g/l); (2) during the withdrawal reaction; and (3) in a control group. The maximal density of [3H] 8-hydroxy-2-(di-n- propylamino)tetralin [( 3H] 8-OH-DPAT) binding (Bmax) to 5-HT1a receptors was decreased by 25 and 17% in the hippocampus during chronic ethanol intoxication and withdrawal, respectively. [3H]Ketanserin binding to 5-HT2 receptors in the cortex, (-)[125I]-iodo-cyanopindolol [( 125I]CYP) binding to 5-HT1b receptors in the striatum and hypothalamus, and [3H] 8-OH-DPAT binding in the cortex were not affected by chronic ethanol administration. Previous in vitro experiments have shown that 5-HT1a receptors in the hippocampus are inhibitory. The down-regulation of these receptors may play a role in physical ethanol dependence, by inducing hyperexcitability of the hippocampus.

Acute effects of ethanol on left ventricular diastolic function.

Transmitral flow velocities were measured by Doppler echocardiography in nine healthy men who ingested 1 g/kg of ethanol within one hour. The measurements were made before the first drink and every hour thereafter for three hours. The peak mean (SE) blood ethanol concentration was 21.4 (1.0) mmol/l. Each man was also studied after drinking fruit juice. Ethanol increased the heart rate but did not change the peak transmitral velocities, the normalised peak filling rate, the deceleration of early flow, or the duration of relaxation as measured from the second heart sound to the peak early diastolic velocity. The ratio of the peak atrial to the peak early diastolic velocity rose from 0.41 (0.03) to 0.44 (0.03) after ethanol but remained unchanged after juice. The difference between juice and ethanol was independent of changes in heart rate. The fluid balance was more negative in the ethanol experiment (-727 (114) ml v -107 (70) ml), suggesting a reduction in preload, and the ethanol-induced net loss of fluid correlated with the concomitant change in the velocity ratio. A moderate dose of ethanol causes a small acute increase of the ratio of the peak atrial to the peak early diastolic velocity of mitral flow in healthy subjects. Although this change indicates altered diastolic function of the left ventricle, most of it may result from the diuretic effect of ethanol. Any major impairment of ventricular relaxation seems unlikely.

The effect of chronic alcohol inhalation on blood pressure and the pressor response to noradrenaline and the thromboxane-mimic U46619

Rats were exposed to alcohol vapor for 6 days and the mean blood ethanol concentration (BEC) was obtained for each subject. Blood pressure and its reactivity to noradrenaline and a thromboxane-mimic U46619 were directly measured on day 6 via a catheter implated in the tail artery of normal and ethanol-treated animals. The mean BEC for each subject correlated with mean arterial blood pressure (MAP); an increase in BEC was associated with a decrease in MAP (p<0.02). The mean MAP of subjects with BEC less than 168 mg% was 8% higher than normal (not significant), whereas, the mean MAP of subjects with BEC greater than 182 mg% decreased 27±4% (p<0.01). Conversely, the pressor response to U46619 was markedly enhanced (p<0.005) in rats with mean BEC greater than 182 mg% at all doses investigated (12.5–3200 ng per rat). Increases in the pressor response to noradrenaline in ethanol-treated rats were significant only when maximally stimulated by 400 and 800ng doses (p<0.03). A 3-fold increase in sensitivity for U46619 was seen in subjects with high mean BEC, however, sensitivity for noradrenaline did not significantly change. Vasoreactivity was not effected in rats with mean BEC less than 168 mg%. These data demonstrate that a moderate mean BEC for 6 days induces a tendency towards a mild hypertension, whereas, high mean BEC induces marked hypotension which is associated with hyperreactivity. Long-term exposure to high blood ethanol concentrations may predispose the alcohol-dependent rats to hypertensive disease and vasospastic disorders, at least partially, as a result of enhanced sensitivity to prostaglandins such as thromboxane.

Effects of ethanol exposure during the third trimester equivalent on neuron number in rat hippocampus and dentate gyrus.

An artificial rearing procedure was used to expose neonatal rats to a formula containing 3.74% ethanol during postnatal days 4 through 10. This treatment produced a mean blood ethanol concentration of 379.8 +/- 17.3 mg/dl. When the pups were killed on the afternoon of postnatal day 10, brain weight to body weight ratio in the ethanol-exposed rats was reduced 22.4% and 21.5% compared to suckle and pair-fed controls, respectively. Ethanol exposure also resulted in a 16% reduction of neurons in hippocampal field CA4, compared to controls, but did not produce deficits in fields CA1 or CA3. There was also a 10% increase in the number of neurons (a population of cells in the midst of a proliferative phase at the time of the exposure) in the granule cell layer of the dentate gyrus. The ethanol exposure did not affect cell size in any of the four neuron populations measured. These results suggest, that within the dose and timing parameters examined, ethanol exposure during the third trimester equivalent appears to be preferentially harmful to specific populations of developing neurons.

Evaluation of breath-alcohol instruments III. Controlled field trial with Alcolmeter pocket model

A breath-alcohol screening device, Alcolmeter pocket model, was evaluated in a controlled field trial with policeman operating the instruments. The results of tests made with subjects before they drank alcohol were always zero. The standard deviation (S.D.) of breath alcohol determinations increased with increase in the concentration of alcohol in the sample, being 0.036 mg/ml at a mean blood-ethanol concentration of 0.53 mg/ml. The S.D. varied among subjects tested (from 0.022 to 0.053 mg/ml) as well as among the instruments used (from 0.023 to 0.054 mg/ml). The breath test results were on average less than the actual blood-ethanol concentrations when a 2100:1 blood/breath ratio was used to calibrate the Alcolmeter device. Blood ethanol ( x) and Alcolmeter readings ( y) were highly correlated ( r = 0.95 ± 0.018) and the regression equation was y = −0.017 + 0.95 x. At a mean blood-ethanol concentration of 0.50 mg/ml, the Alcolmeter instrument will indicate 0.46 mg/ml on average. The standard error estimate was 0.085 mg/ml, being 17% of the mean Alcolmeter reading and this corresponds to 95% confidence limits of ±0.17 mg/ml. The results of this study show that Alcolmeter pocket-model is a useful device for breath-alcohol screening purposes at a blood-alcohol level of 0.50 mg/ml. A blood/breath ratio of 2300 should be used to calibrate the Alcolmeter device.