Corticosterone concentrations in mice during ethanol drinking and withdrawal

Effects of alcohol on the synthesis and expression of hypothalamic peptides

Studies aimed at analyzing the deleterious effects of excess alcohol in the brain have revealed structural alterations that are often associated with functional and behavioral disturbances. Among the neuronal damage related to prolonged alcohol exposure, alterations in the synthesizing capabilities and levels of expression of neuroactive peptides have been increasingly reported. Actually, such changes frequently represent the sole repercussion of acute and short-term exposure to ethanol. This review gathers the existing data on the effects of ethanol exposure on the synthesis and expression of hypothalamic peptides. Amid those that can act both as neurotransmitters and neurohormones, we allude to vasopressin, corticotropin-releasing hormone, thyrotropin-releasing hormone and pro-opiomelanocortin and related peptides produced by paraventricular, supraoptic and arcuate neurons. With respect to peptides that act exclusively as neurotransmitters, we address the effects of alcohol on vasoactive intestinal polypeptide, gastrin-releasing peptide, somatostatin and vasopressin synthesized by suprachiasmatic neurons. Hypothalamic neurons that produce peptides that act as neurotransmitters are supposed to be modulated primarily by influences exerted by neuronal afferents, whereas those producing peptides that additionally act as neurohormones are also regulated by peripheral stimuli (e.g., plasma levels of circulating hormones, osmotic challenges). These peculiar features endue the hypothalamus with characteristics that are particularly propitious to enlighten the still cryptic mechanisms underlying the ethanol effects on protein synthesis.

Chronic ethanol administration alters the modulatory effect of 5alpha-pregnan-3alpha-ol-20-one on the binding characteristics of various radioligands of GABAA receptors

In this study, we investigated the modulatory effect of 5alpha-pregnan-3alpha-ol-20-one, a neurosteroid, on the binding characteristics of [3H]flunitrazepam (2 nM), [3H]muscimol (5 nM), and 4 nM [35S]t-butylbicyclophosphorothionate (TBPS) in cerebral cortex, cerebellum, and hippocampus of control, ethanol-dependent, and ethanol-withdrawn rats. 5alpha-Pregnan-3alpha-ol-20-one potentiated the binding of [3H]flunitrazepam and [3H]muscimol in all the rat brain regions investigated in this study. There was a significant increase in the maximal potentiation of [3H]flunitrazepam as well as [3H]muscimol binding (Emax) in the ethanol-dependent rat cerebellum as compared to control group (p<0. 025). Furthermore, 5alpha-pregnan-3alpha-ol-20-one elicited a biphasic response, i.e., it potentiated the binding of [35S]TBPS at lower concentrations (<=100 nM) and inhibited the binding at higher concentrations (>100 nM). There was a significant higher inhibition of [35S]TBPS binding (-Emax) by 5alpha-pregnan-3alpha-ol-20-one in the hippocampus of ethanol-dependent as well as ethanol-withdrawn rats (p<0.025). These observations suggest that the neurosteroid binding site associated with the gamma-aminobutyric acidA (GABAA) receptors in cerebellum and hippocampus plays an important role during ethanol-dependence and ethanol-withdrawal, and some of the changes following ethanol dependence and its withdrawal may be mediated through the neurosteroid binding site.

Dexamethasone in the treatment of the alcohol withdrawal syndrome

Pre-clinical studies and clinical case reports suggest that glucocorticoids may be efficacious in ameliorating the signs and symptoms of the alcohol withdrawal syndrome. In order to evaluate the efficacy of the glucocorticoid dexamethasone upon alcohol withdrawal, we administered 4 mg of dexamethasone intravenously to eight alcohol dependent men during withdrawal. Withdrawal severity, as determined by the amount of lorazepam required to ameliorate withdrawal symptoms, was compared to eight other withdrawing patients not administered dexamethasone. There was no significant difference between the two groups in the amount of lorazepam required to treat to withdrawal symptoms. This preliminary study suggests that dexamethasone, in doses expected to suppress hypothalmic-pituitary-adrenal axis activation, is not efficacious in the treatment of alcohol withdrawal.

Behavioral sensitization to ethanol: genetics and the effects of stress

Some aspects of drug abuse syndromes may be influenced by sensitization to some drug effects. This enhancement of drug effect has been associated with prior drug exposure and with exposure to stressful stimuli. It has been postulated that sensitization to psychomotor stimulant drug effects influences sensitivity to drug reward. The drugs of abuse best characterized for sensitization phenomena include cocaine, amphetamine, and morphine. In general, ethanol's molecular mechanisms of action have been difficult to define relative to drugs with known receptor or transporter binding sites and, likewise, ethanol sensitization has been less thoroughly examined. Evidence supporting the existence of behavioral sensitization to ethanol, for genetic differences in the occurrence of ethanol sensitization, and for the influence of corticosterone on the development of ethanol sensitization is reviewed herein. There appear to be different genetic determinants of acute drug sensitivity and sensitization. Cross-sensitization between stress and ethanol suggest a potential role for hypothalamic-pituitary-adrenal (HPA) axis associated changes in ethanol sensitization, consistent with mechanisms likely contributing to sensitization to other abused drugs. Furthermore, glucocorticoid receptors appear to mediate both ethanol- and stress-induced sensitization to ethanol. A biological link between drug reward and drug sensitization involving HPA axis hormones may exist and, thus, study of the sensitization process may elucidate mechanisms relevant to drug abuse.

Influence of exercise and ethanol on cholinesterase activity and lipid peroxidation in blood and brain regions of rat

1. This study elucidates the interaction of acute exercise and single ethanol intake on cholinergic enzyme and its relationship to lipid peroxidation in the blood and brain regions of the rat. 2. Butyrylcholinesterase (BuChE) in plasma and acetylcholinesterase (AChE) in brain regions as well as lipid peroxidation (MDA) were assayed in 1) sedentary control rats; 2) after acute exercise (100% VO2max); 3) ethanol 20% (1.6 gm/kg, p.o.); 4) exercise and then ethanol 20% (1.6 gm/kg, p.o.). 3. Acute exercise significantly increased BuChE activity (155% of control) in plasma and decreased AChE activity (60% of control) in the corpus striatum with a significant increase in the striatal MDA level (254% of control). Ethanol significantly decreased AChE activity only in striatum (86% of control) with a significant increase in striatal MDA level (132% of control). 4. The combination of exercise and ethanol 20% (1.6 gm/kg, p.o.) significantly increased BuChE activity (123% of control) in plasma, and decreased AChE activity (76% of control) in striatum with significant increase in striatal MDA level (147% of control). 5. Acute exercise, single ethanol 20% (1.6 gm/kg, p.o.) intake and the combination selectively inhibited striatal AChE, and the inhibition was correlated with increased lipid peroxidation indicating perturbation of motor function. The combination reduced the peripheral stress response caused by exhaustive exercise.

Chronic alcohol consumption and withdrawal do not induce cell death in the suprachiasmatic nucleus, but lead to irreversible depression of peptide immunoreactivity and mRNA levels

There is evidence that chronic ethanol treatment (CET) disrupts the biological rhythms of various brain functions and behaviors. Because the suprachiasmatic nucleus (SCN) is widely recognized as the dominant pacemaker of the circadian system, we have examined the effects of CET and withdrawal on the main morphological features and chemoarchitecture of this hypothalamic nucleus. Groups of rats ethanol-treated for 6 and 12 months were compared with withdrawn rats (ethanol-treated for 6 months and then switched to a normal diet for an additional 6 months) and with groups of age-matched control and pair-fed control rats. The volume and the total number of neurons of the SCN were estimated from conventionally stained material, whereas the total number of astrocytes and of neurons containing vasopressin (AVP), vasoactive intestinal polypeptide (VIP), gastrin-releasing peptide (GRP), and somatostatin (SS) were estimated from immunostained sections. The estimates were obtained using unbiased stereological methods, based on Cavalieri's principle and the optical fractionator. The volume of the SCN and the total number of SCN neurons and astrocytes did not vary among groups. We found, however, that CET induced a significant reduction in the total number of AVP-, VIP-, GRP-, and SS-containing neurons. Withdrawal from alcohol did not reduce but rather augmented the loss of VIP- and GRP-immunoreactive neurons. The CET-induced neurochemical alterations seem to result from a decrease in neuropeptide synthesis, as revealed by the reduction in AVP and VIP mRNA levels demonstrated by in situ hybridization with radioactively labeled 48-mer AVP and 30-mer VIP probes. It is thus possible to conclude that the irreversible CET-induced changes in the neurochemistry of the SCN might underpin the disturbances in circadian rhythms observed after long-term alcohol consumption.

Adrenalectomy prevents the development of alcohol preference in male rats

By forcing adrenalectomized (ADX) and sham-operated (SHAM) rats to chronically drink ethanol by mean of presentation of only one drinking bottle containing 10% ethanol, no differences occurred between both groups. ADX and SHAM rats were then exposed to chronic alcoholization using an inhalation procedure. After sejourning 3 weeks into the alcoholization chamber, rats were submitted to a free-choice paradigm [water vs. a 10% (v/v) ethanol solution]. The sham-operated rats presented an alcohol-induced behavioral preference towards alcohol whereas adrenalectomized animals never exhibited a preference to ethanol. In the adrenalectomized rats treatment with hydrocortisone (30 micrograms/ml) given orally during the pulmonary alcoholization failed to modify this preference whereas treatment with corticosterone (25 micrograms/ml) given orally abolished the difference with SHAM animals. These data showed that adrenalectomy prevented the development of ethanol preference and the clear involvement of the hypothalamo-pituitary-axis in alcohol preference.

Development and characterization of a binge drinking model in mice for evaluation of the immunological effects of ethanol

This study describes the development and characterization of a binge drinking model in which a single dose of ethanol (EtOH) is administered by gavage to B6C3F1 mice. Blood EtOH levels were monitored over time after administration of EtOH at doses of 3.0-7.0 g/kg. Peak levels were in the range of 0.2-0.5%, and clearance was complete within 2-12 hr. Substantial increases in blood corticosterone levels were noted. Behavioral changes in EtOH-treated mice aged 8 weeks ranged from no effect (3-4 g/kg) to severe ataxia (6-7 g/kg). In mice aged 16 weeks, a dosage of 7 g/kg caused less of the righting reflex in some animals and severe ataxia in most of the others. Clinical chemistry results did not indicate biologically important changes in general physiological/homeostatic systems in EtOH-treated mice, but there were indications of minor liver damage at the 7 g/kg dosage. Thus, administration of EtOH to B6C3F1 mice by gavage produces behavioral changes, changes in blood EtOH levels, and probably glucocorticoid levels representative of at least some human binge drinkers. The model was used to evaluate the effects of binge drinking on antibody responses, and the results indicate the model will be useful for such studies.

Vitamins and immunomodulation in AIDS

Acquired immune deficiency syndrome (AIDS) is a clinical disorder caused by a retrovirus infection and represents the end point in a progressive sequence of immunosuppressive changes. Vitamins can enhance disease resistance in animals and humans. As such they are important co-factors in optimal functioning of the immune systems. In this article, the immunological and nutritional modifications caused by AIDS are summarized. The effects of murine and human retrovirus infection on vitamin status are analyzed as co-factors in the development of severe immune dysfunction, AIDS. The properties of immunoenhancing antioxidative vitamins, vitamin A, B6, B12, C, E, and beta-carotene, which are frequently low in AIDS patients, are evaluated relative to the development of immunodeficiency during retrovirus infection. Vitamin A, E, and B12 deficiency accelerated the development of AIDS with low T cells, whereas their normalization retarded the development of immune dysfunction. The interactions between these vitamins and the immune system in human AIDS patients and animal models of AIDS are reviewed. Our purpose is to provide data on how retrovirus infection can cause nutritional deficiencies that accentuate immune damage and to evaluate the potential therapeutic role of vitamins in the treatment of immune dysfunctions in AIDS patients.

Rapid changes in cytochrome P4502E1 (CYP2E1) activity and other P450 isozymes following ethanol withdrawal in rats

This study describes the effects of chronic ethanol (ETOH) treatment and withdrawal on the rat hepatic mixed-function mono-oxygenase system. Male Sprague-Dawley rats (150-200 g, 10 per group) were administered ETOH as part of the Lieber-deCarli liquid diet for 3 weeks. Ethanol was removed, and the animals were euthanized at 0, 24, 48, 72 and 168 hr post-withdrawal. Microsomes were prepared, and ethanol-inducible cytochrome P4502E1 (CYP2E1) activity was measured using the enzyme markers N-nitrosodimethylamine demethylase (NDMAd), p-nitrophenol hydroxylase (PNPH) and aniline hydroxylase (AH). Activities were found to be induced significantly after chronic ETOH feeding using all three assays (NDMAd, 5-fold; PNPH, 3.5-fold; AH, 9-fold). Upon ETOH withdrawal, all three activities dropped markedly, with NDMAd and PNPH at control values at 24 hr and all subsequent time points. AH activity remained 3-fold higher than controls at 24, 48 and 72 hr. Western blot analyses showed that immunoreactive CYP2E1 returned to control at 24 hr, consonant with NDMAd and PNPH activities. The prolonged induction of AH activity following ETOH withdrawal indicates that it is not a specific marker of CYP2E1-catalyzed reactions. Collectively, these data are suggestive of a rapid mechanism of CYP2E1 degradation in the rat liver. Of the other parameters investigated in this study, total cytochrome P450 content was increased 2.5-fold after ETOH feeding, with levels dropping markedly 24 hr post-withdrawal. NADPH-dependent cytochrome c reductase activity was unchanged throughout the course of the study. CYP1A1, CYP2B1 and CYP3A activities were assessed by the substrate probes ethoxyresorufin O-dealkylase (EROD), pentoxyresorufin O-dealkylase (PROD) and erythromycin N-demethylase (ERNd). EROD and PROD were induced significantly by ETOH administration (2-fold) at 0 hr, with EROD remaining elevated over controls 24 hr post-withdrawal. Quantitative western blot analysis of CYP1A1 and CYP2B1 revealed a pattern of immunostaining generally consistent with but less variable than levels predicted by the respective substrate markers. Both proteins were induced significantly by chronic ethanol administration (CYP1A1, 1.9-fold; CYP2B1, 4-fold). Induction of these P450 isoforms persisted for several days following withdrawal. In contrast, immunoreactive CYP1A2 was found to decrease significantly (by 30-40%) during ethanol withdrawal (24, 48, 72, 168 hr). ERNd activity was induced significantly by chronic ETOH feeding (2.5-fold) and remained so for 24 hr into the withdrawal period (2-fold). Immunoreactive CYP3A1 was also induced significantly following ETOH administration (0 hr) and 24 hr following withdrawal.(ABSTRACT TRUNCATED AT 400 WORDS)

The neurosteroid, 3 alpha-hydroxy-5 alpha-pregnan-20-one, protects against bicuculline-induced seizures during ethanol withdrawal in rats

Prolonged alcohol consumption leads to the development of tolerance to and dependence on ethanol, resulting in a decreased response to the sedative/hypnotic effects of ethanol, and by negative symptomatology following abrupt termination of use. One symptom associated with ethanol withdrawal in humans, as well as laboratory animals, is enhanced susceptibility to seizures. This study investigated the effects of the neurosteroid, 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha-5 alpha-THP), on alterations in seizure sensitivity associated with ethanol withdrawal. 3 alpha-5 alpha-THP is a potent anxiolytic and anticonvulsant agent that acts via selective interactions with GABAA receptors. Extensive evidence suggests that some aspects of ethanol dependence and withdrawal are mediated by alterations in GABAA receptor function. Withdrawal from chronic ethanol exposure elicited dramatic increases in seizure susceptibility in male and female rats. Administration of 3 alpha-5 alpha-THP just before seizure threshold determinations blocked the increased seizure susceptibility induced by ethanol withdrawal. Ethanol-withdrawn animals were protected by 3 alpha-5 alpha-THP at a dose that had no effect on control animal seizure thresholds. Moreover, male and female rats displayed differential responses to the seizure-threshold lowering effects of ethanol withdrawal, as well as the protection by 3 alpha-5 alpha-THP pretreatment. These findings suggest that there are gender differences associated both with ethanol withdrawal as well as the protection by 3 alpha-5 alpha-THP in ethanol-dependent rats.

Ethanol consumption reduces the cytolytic activity of lymphokine-activated killer cells

Ethanol (20% w/v) given to female C57BL/6 mice in their drinking water reduces splenic natural killer (NK) cell cytolytic activity after 2, 4, and 10 weeks of consumption. This reduction is transient because the levels of NK cell cytotoxicity from ethanol-consuming mice are nearly equal to those of water-drinking mice after splenocytes were incubated in 1000 IU/ml of recombinant interleukin-2 (rIL2) for 16-18 hr. In this study, mice were given 20% w/v ethanol in the drinking water for 2 weeks. Splenic NK cells were enriched up to 88% by negative selection based on surface expression of NK1.1. Enriched NK cells were expanded in rIL2 for 6 days. Lymphokine-activated killer (LAK) cells from both ethanol-consuming and water-drinking mice were > 95% NK1.1+. LAK cell cytolytic activity was significantly lower against NK-insensitive P815 mastocytoma [6.67 +/- 2.18 vs. 17.21 +/- 1.8 lytic units (LUs), p < 0.01], moderately NK-sensitive B16 melanoma (25.3 +/- 6.6 vs. 66.2 +/- 14.2 LU, p < 0.05), and NK-sensitive YAC-1 lymphoma targets (80.5 +/- 34.7 vs. 177.0 +/- 43.6 LU, p < 0.005) in cells from ethanol-consuming mice compared with water-drinking controls. Ethanol consumption did not affect the morphology or phenotype of LAK cells with respect to surface expression of NK1.1, B220, CD3, CD25, CD11a, CD54, CD45RB, or class I major histocompatibility complex.

Ethanol-induced depletion of lymphocytes from the mesenteric lymph nodes of C57B1/6 mice is associated with RNA but not DNA degradation

The effects of ethanol (EtOH) consumption by adult female C57B1/6 mice on lymphocyte populations of the mesenteric lymph nodes (MLNs) were determined by feeding mice with the Lieber-DeCarli liquid diet by a pair-feeding paradigm. Histological analysis of the MLNs of EtOH-fed mice showed a progressive loss of lymphocytes from the medullary regions at 3, 5, and 7 days after initiation of the EtOH diet. The stromal cells in the medullary region also demonstrated a progressive alteration in stellate morphological features at times corresponding to those of loss of lymphocytes from this region. Microscopic evaluation of the follicle regions of MLNs obtained from mice fed an EtOH-containing diet showed no appreciable alterations in morphological characteristics. The number of tingible body macrophages in the germinal centers of the follicles, however, was increased after 3 days of EtOH diet feeding and declined progressively after this time. Flow cytometric analysis of isolated lymphocytes showed a depletion of both T and B cell populations from the MLNs. In contrast to B cells, however, T cells were depleted through 7 days of EtOH diet feeding. Total RNA isolated from the MLNs of mice consuming the EtOH-containing diet was progressively degraded. No degradation of DNA was observed. These study results establish that continuous consumption of dietary EtOH adversely affects the cellularity of MLN, resulting in a progressive loss of lymphocytes that is associated with degradation of total RNA.

Corticosterone increases severity of acute withdrawal from ethanol, pentobarbital, and diazepam in mice

It has been suggested that withdrawal from several subclasses of central nervous system (CNS) depressants involves common underlying mechanisms. For example, mice genetically selected for severe ethanol withdrawal convulsions (Withdrawal Seizure Prone or WSP) have also been found to express severe withdrawal following treatment with barbiturates and benzodiazepines. Corticosteroids appear to modulate severity of withdrawal from CNS depressants. Therefore, it was hypothesized that corticosterone would enhance withdrawal convulsions following acute ethanol, pentobarbital, and diazepam in WSP mice. Corticosterone (20 mg/kg) administered following each of these drugs significantly increased severity of handling-induced convulsions during withdrawal. Corticosterone did not affect pre-withdrawal convulsion scores or handling-induced convulsions of drug-naive mice. These results suggest that withdrawal convulsions following acute ethanol, pentobarbital, and diazepam are sensitive to modulation by corticosterone and they support the hypothesis that stress may increase drug withdrawal severity.

Dietary vitamin E modulation of cytokine production by splenocytes and thymocytes from alcohol-fed mice

As vitamin E enhances immune responses, it may reduce dietary ethanol (EtOH)-induced immune suppression, thereby favorably affecting host disease resistance. The effects of dietary vitamin E at higher level in alcohol-fed female C57BL/6 mice was determined via in vitro cytokine production by splenocytes and thymocytes, and some other immune functions. A 15-fold increase of vitamin E (160 IU/liter) in a liquid diet (National Council Research), with or without EtOH (4.5%, v/v), was fed to mice for 10 weeks. Vitamin E supplementation restored production of interleukin-2, -5, -6, -10, and interferon-gamma by concanavalin A (Con A)-stimulated splenocytes and interleukin-6 and tumor necrosis factor-alpha by lipopolysaccharide-stimulated splenocytes, which were suppressed by dietary EtOH. However, it had no effect on interleukin-4 secretion, which was also reduced by splenocytes from EtOH-fed mice. Vitamin E supplementation also restored EtOH-suppressed, mitogen-induced splenocyte proliferation, but not thymocyte proliferation, although it slightly increased production of immunoglobulin A and G by lipopolysaccharide-stimulated splenocytes, which were suppressed by dietary EtOH. Dietary vitamin E, furthermore, significantly increased interleukin-2 and -6 secretion by Con A-stimulated thymocytes, which were suppressed by dietary EtOH, although it had no effect on interleukin-4 and interferon-gamma production by Con A-stimulated thymocytes from EtOH-fed mice. These data suggest that dietary vitamin E supplementation can modulate dysregulation of cytokines initiated by dietary EtOH and restore immune dysfunctions induced by EtOH ingestion.

Ethanol, immune responses, and murine AIDS: the role of vitamin E as an immunostimulant and antioxidant

Excessive alcohol consumption is a major health problem in the United States. Prolonged consumption of alcohol results in alterations of immune responses, ultimately manifested by increasing susceptibility to infectious agents. Such changes can be due to the direct effects of alcohol or its metabolites on immune cells, as well as to nutritional deficiency, oxidative stress, and neutrophil dysfunctions. This ETOH-induced immunosuppression could be a potential cofactor in the progression to AIDS. As vitamin E supplementation has been associated with enhancement of immune response and improvement of host defense, it may provide a useful therapeutic approach for treatment of alcoholics to improve host defense. This article is a review of alcohol-related immunosuppression as a possible cofactor in the development of AIDS, and vitamin E-related immunoenhancing roles in animals and humans, showing why vitamin E supplementation could be used as a useful adjunct agent in alcoholics' treatment. Since there is little information available regarding nutritional therapy with alcohol users, our purpose is to provide evidence from animal models of the potential therapeutic role of vitamin E supplementation in the treatment of alcoholics.

Are binge drinkers more at risk of developing brain damage?

Alcoholism is often associated with brain damage and cognitive deficits. Because drinking patterns can include periods of alcohol consumption followed by abstinence, binge drinking may enhance the possibility of brain damage. Chronic administration of ethanol leads to upregulation of N-methyl-D-aspartate (NMDA) and calcium receptors and increased release of glucocorticoids. NMDA-mediated mechanisms and glucocorticoid actions on the hippocampus are associated with brain damage. Thus, ethanol withdrawal may make the brain more vulnerable to damage from these mechanisms, especially with binge drinking. Therapeutic adjuncts for treating ethanol withdrawal, including NMDA, calcium, and glucocorticoid antagonists, may eventually prove useful in preventing further brain damage in alcoholism.

Type I corticosteroid receptors modulate PTZ-induced convulsions of withdrawal seizure prone mice

Corticosteroids have been shown to modulate convulsion expression in humans and animals. It is hypothesized that type I corticosteroid receptors mediate the excitatory effects of corticosteroids in vivo based on low-dose efficacy of corticosterone, and differential effects of mineralocorticoids vs. glucocorticoids on convulsions. In the present experiments, the effects of altering corticosterone levels, and the role of the type I receptor in mediating these effects, were examined using pentylenetetrazol (PTZ)-induced convulsions in ethanol withdrawal seizure prone (WSP) mice. It was hypothesized that stimulation of type I receptors partially mediates the expression of tonic hindlimb extensor (THE) convulsions produced by PTZ. Aminoglutethimide, a steroid synthesis inhibitor, increased latencies to PTZ-induced THE. This anticonvulsant effect was reversed by corticosterone and the type I agonist, deoxycorticosterone (DOC), but not by the type II agonist, dexamethasone. Furthermore, two type I receptor antagonists, spironolactone and RU26752, increased latencies to PTZ-induced THE, suggesting that they have anticonvulsant action. In summary, the results of these experiments suggest that type I corticosteroid receptors are important for expression of PTZ-induced convulsions.

Immunosuppression in adult female B6C3F1 mice by chronic exposure to ethanol in a liquid diet

The overall objective of these studies was to characterize the effects of ethanol on the immunocompetence of adult female B6C3F1 mice. To obtain a significant suppression in the antibody response to SRBC, splenocytes from untreated mice had to be directly exposed to concentrations of ethanol from 0.3% to 3.0%, or to acetaldehyde at concentrations greater than 0.03%. We do not believe that these results are consistent with a role by a direct effect by either ethanol or its primary metabolite because these concentrations are higher than what could be obtained as reasonable blood levels. For in vivo exposure, we employed a pair-feeding regimen which was based on a liquid diet containing 5% ethanol (v/v) that provided 36% of the caloric intake as ethanol. Our results indicated that there was a definite temporal relationship to the consequent suppression of the antibody response to SRBC in that no effect was observed after 14 days exposure, and that the magnitude of the suppression increased from 18% after 21 days to 70% after 42 days. We also monitored the liver for histopathology and observed that the ethanol-induced liver damage was restricted to steatosis (fatty liver), which was also manifested with time and which was most pronounced after 42 days exposure. In contrast to our results with the in vivo antibody response, we saw no effect on mitogen-induced proliferation by splenocytes from ethanol-treated mice. These results prompted us to measure in vitro antibody responses by splenocytes from ethanol-treated mice. We saw no suppression of the in vitro antibody responses to SRBC, DNP-Ficoll or LPS after any length of exposure to ethanol, and speculated that the basis for the suppression of the in vivo antibody response was an indirect consequence of exposure. We subsequently determined that when normal splenocytes were cultured in 5% serum from ethanol-exposed mice (42-day group), there was a > 80% suppression relative to the serum from the pair-fed controls. As important controls for these studies, we have demonstrated that there was no difference between the responses of normal lymphocytes cultured in 5% normal mouse serum and in 5% serum taken from the pair-fed restricted controls. A determination of the ethanol content in the serum from ethanol-exposed mice (42-day group) indicated that the amount of ethanol present in these cultures was < 0.003%.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of chronic ethanol administration on the rat pineal N-acetyltransferase and thyroxine type II 5'-deiodinase activities

Chronic ethanol intake resulted in a significant decrease in the rate of ponderal growth and an impaired nyctohemeral profile of pineal N-acetyltransferase (NAT) activity. In ethanol-treated animals, the onset of the nocturnal NAT increase is delayed by 2 hours when compared to control animals. Moreover, pineal NAT nocturnal peak was reached at 4 h (2 hours later than controls), while pineal type II thyroxine 5'-deiodinase (5'-D) nyctohemeral profile was not modified by ethanol administration. The effect of ethanol administration (12 weeks) on 5'-D activity in different tissues was also studied. Ethanol induced a 5'-D activity increase in hypothesis and brain frontal cortex, when compared to control animals. No change in 5'-D activity is observed in either pineal gland, Harderian gland, or brown adipose tissue. Since basal values of 5'-D activity in hypophysis or brain frontal cortex are particularly dependent on serum thyroxine (T4) concentration, the effect of chronic ethanol administration on thyroid hormone levels was studied. Serum T4 levels in ethanol-treated animals were significantly decreased when compared to controls at any time point studied. However, no change in serum 3',3,5-triiodothyronine (T3) levels were found.

Ethanol increases apoptotic cell death of thymocytes in vitro

Exposure of animals to ethanol causes thymic atrophy in adults and fetuses. Whether direct effects of ethanol contribute to thymic atrophy or whether indirect effects are entirely responsible is at present unknown. In the normal animal, large numbers of thymocytes undergo a physiological form of cell death referred to as "apoptosis." To determine if ethanol affects the process of apoptosis, studies were undertaken in which mouse thymocytes were cultured overnight in the presence or absence of ethanol. Apoptotic cell death was analyzed by flow cytometric quantitation of apoptotic nuclei, by fluorometric measurement of DNA fragments, and by gel electrophoretic analysis of DNA fragments. Ethanol in concentrations of 0.2% to 0.8% produced significantly higher levels of apoptosis than were seen in control cultures. The DNA fragmentation was characterized as apoptotic on the basis of inhibition by aurintricarboxylic acid (an inhibitor of nucleases) and by the presence of characteristic oligonucleosomal-sized fragments of DNA. The effect of ethanol on apoptosis was additive to that induced by immobilized anti-CD3 monoclonal antibody. CD4+CD8+ cells underwent apoptosis as indicated by reduction in CD4 and CD8 surface antigen expression. An inhibitor of protein kinases (H-7) reduced the DNA degradation induced by ethanol and by anti-CD3. These results suggest that direct effects of ethanol contribute to thymic atrophy in alcohol-consuming animals.

The effects of alcohol on murine macrophage function

Animal models used to measure the effects of alcohol on lymphoid cells and their functions provide useful ways to evaluate the multisystem effects of this substance. The effects of ethanol ingestion on the function of murine peritoneal macrophages (M phi) was evaluated. Both the production of reactive oxygen intermediates (ROI) and the ingestion of foreign particles (phagocytosis) were studied. Mice were pair fed ad libitum a nutritionally complete liquid diet containing 7% v/v ethanol or a calorically balanced control diet. Two regimens were employed for the administration of the diets. One regimen represented "binge" drinking (short term-4 days) while the other represented "chronic" consumption (long term-14 days). Following the short term administration of the diets, an increase in the respiratory burst (RB), as well as a decrease in phagocytosis, were observed with M phi from the ethanol fed mice. The decrease in phagocytosis, was noted using either in vitro or in vivo methods. Results observed after long term administration indicated no significant change in the RB or in in vitro phagocytosis between the ethanol and control groups. Phagocytosis measured in vivo, however, was decreased in M phi from ethanol fed mice following long term administration. These results indicate an alteration in murine peritoneal M phi function following short term an long term administration of alcohol.

Specific and nonspecific effects of ethanol vapor on plasma corticosterone in mice

The intent of this study was to determine whether chronic ethanol (EtOH) vapor inhalation, with or without adjunct pyrazole (PYR) administration, was stressful in mice, as defined by increases in plasma corticosterone (CORT) concentration. Mice were randomly assigned to groups differentiated both on the basis of EtOH vapor exposure and the presence or absence of PYR administration. Blood samples for blood EtOH concentration (BEC) and plasma CORT concentration were obtained from mice after 72-96 hours of treatment. Mice were sacrificed after 96 hours of treatment and body and adrenal weight determined. BEC was significantly higher in PYR-treated animals and animals treated with the higher EtOH vapor concentration. Plasma CORT was elevated in proportion to BEC; however, other nonspecific stresses, in particular that of PYR administration, also elevated plasma CORT. Nonspecific stresses associated with this protocol may reduce the generality of these observations. Nevertheless, the high correlation between BEC and plasma CORT concentration in the PYR groups indicates that, with suitable control groups, the PYR-EtOH vapor inhalation approach is viable for studies concerned with EtOH effects on hypothalamic-anterior pituitary-adrenocortical function.

Genetic differences in hypothalamic-pituitary-adrenal axis responsiveness to acute ethanol and acute ethanol withdrawal

There is a growing body of evidence suggesting that corticosteroids contribute to the increased neural excitability observed during ethanol withdrawal. In the present study, this was further investigated using mouse strains which differ in ethanol withdrawal severity. DBA/2 (DBA) mice were found to display more severe acute ethanol withdrawal seizures than C57BL/6 (C57) mice. Additionally, DBA mice showed a greater stress response than C57 mice, as measured by higher plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone, to an acute dose of ethanol. Mimicking withdrawal plasma corticosterone levels by administering corticosterone to ethanol-naive mice resulted in increases in handling-induced convulsions in the range observed during withdrawal. There did not appear to be a strain difference in sensitivity to the excitatory effects of corticosterone. In summary, the greater stress response to ethanol by DBA mice may account, in part, for the more severe ethanol withdrawal syndrome of this strain.

Immune response to the Lyme spirochete Borrelia burgdorferi affected by ethanol consumption

Rats fed excessive amounts of ethanol developed marked hematologic and immunologic changes. These included a reversal of the normal lymphocyte to granulocyte ratio in the peripheral blood, lower spleen and lymph node weights and a greatly reduced capacity to express normal cell mediated immune functions, based on poor lymphocyte reactivity in vivo, and in vitro to T and B cell mitogens and borrelial antigens shortly after primary immunization with the bacterial spirochete, Borrelia burgdorferi. Further evidence for impaired immune function caused by ethanol was based on little or no antibody response against Borrelia in rats following in vivo sensitization with B. burgdorferi incorporated in complete Freund's adjuvant. These findings provide substantial direct evidence strengthening the notion that high levels of ethanol ingestion adversely affect the host immune system and can interfere with the immune response to microorganisms.

Flow cytometric and immunohistochemical evaluation of ethanol-induced changes in splenic and thymic lymphoid cell populations

Ethanol-induced alterations in the immune system are thought to play a major role in increasing the susceptibility of alcoholics to infections and tumors. One important change in the immune system is the noted loss of lymphoid cells from the thymus and spleen. To examine these alterations we used a model system where C57Bl/6 mice were pair-fed either a Leiber-DeCarli diet containing 7% (v/v) ethanol or an isocaloric control diet. Mice receiving ETOH for 7 days showed a loss of cells from the spleen and thymus; this loss was even more severe after withdrawal for 1 day. The most profound changes were seen after 2 weeks of ETOH. Spleen and thymus cell numbers were reduced to 36% and 6.2%, respectively compared to control mice. Staining of thymocytes with monoclonal antibodies to lymphocyte surface markers and evaluation with flow cytometry revealed that immature thymocytes (PNA+, CD4+/CD8+) were most reduced. Mature thymocytes (CD4+/CD8- or CD4-/CD8+) were depleted, and the CD4+ to CD8+ ratio was increased. Sections of thymus stained with hematoxylin and eosin or with immunohistochemical methods showed atrophy and lymphoid cell depletion. No cortex was histologically identifiable after 2 weeks of ETOH. The spleen cells most affected by ETOH were the B cells. They were reduced to 8.2 x 10(6) cells/spleen (31.5% of the lymphocytes), as compared to 38.5 x 10(6) cells/spleen (50.3% of the lymphocytes) in the control mice. The spleen was atrophic, but the immunoarchitecture was preserved. Ethanol causes a depletion of lymphocytes from the spleen and thymus with alterations in lymphocyte subpopulations.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential modulation by the stress axis of ethanol withdrawal seizure expression in WSP and WSR mice

Withdrawal from both acute and chronic ethanol (EtOH) exposure is associated with increased neural excitability and increased activity of the hypothalamic-pituitary-adrenal axis. There is some evidence that glucocorticoids are necessary for EtOH withdrawal seizure expression. Lines of mice that were selected for severe (WSP) and minimal (WSR) EtOH withdrawal (as estimated from handling-induced convulsion scores) have been shown to differ in their stress response following an acute dose of EtOH. In this study we provide evidence that these lines of mice also differ in their sensitivity to the excitatory effects of glucocorticoids. EtOH withdrawal seizures of WSP mice were significantly increased by chronic and acute corticosterone treatment, whereas those of the WSR mice were unaffected. Neural excitability was decreased in the WSP mice when aminoglutethimide, a glucocorticoid synthesis blocker, was administered. Thus, it appears that genetic differences in EtOH withdrawal seizure severity may be due, in part, to differences in sensitivity to the excitatory effects of glucocorticoids.

Lower serum osteocalcin in ethanol-fed rats

Serum osteocalcin was remarkably and significantly (-34 and -41% in two separate experiments; p less than 0.001) lower in rats fed an 8% (w/v) ethanol liquid diet (ELD) for 1 week than in rats fed an isocaloric control liquid diet (CLD). In a longer experiment that spanned 4 weeks, the ELD rats were given 6% ethanol on day 4, increased stepwise to 8% by day 9, and then maintained at 8% until day 28, when the experiment was terminated. Again, serum osteocalcin was much lower (-32%, p less than 0.001) in the ELD-fed rats than in CLD-fed rats. Even in rats fed only a 6% ELD for 12 days, serum osteocalcin was lower (-33%, p less than 0.001) than in controls. Also, the femora were weaker, more compliant, and more ductile in ELD-than in CLD-fed rats, findings that confirmed our earlier, related work. The fall in serum osteocalcin in ELD-fed rats is associated with a fall in femur ash weight and bone strength. There were significant correlations between serum osteocalcin and bone strength (r = 0.80; p less than 0.001) and between serum osteocalcin and bone stiffness (r = 0.83; p less than 0.001). Serum ionized calcium, like osteocalcin, was consistently lower in rats given ethanol for 1 or 4 weeks than in controls. From these experiments we conclude that excessive ethanol consumption inhibits osteoblastic activity as indicated by the reduced serum osteocalcin. The inhibition is also associated with other deleterious effects of ethanol on bone, including ash weight, bone strength, and bone stiffness.(ABSTRACT TRUNCATED AT 250 WORDS)

Murine model of ethanol-induced immunosuppression

Alcohol abuse has been associated with an increased susceptibility to infectious diseases and certain tumors. On the basis of these observations, an effect of ethanol on the immune system has been suggested. We have used a mouse model system in which male C57Bl/6 mice were fed either Lieber-DeCarli liquid diet containing ethanol sufficient to supply 37% of the total calories or isocaloric control diet in a pair-feeding design to examine the effect of ethanol on the immune system. The group consuming the ethanol-containing diet maintained relatively stable levels of blood ethanol for the 8 days of feeding. Consumption of ethanol for 8 days resulted in a profound loss of thymus and spleen cells, and the recovery of thymus cellularity was delayed relative to the recovery of spleen cell numbers after ethanol feeding was discontinued. Proliferation of spleen lymphocytes to T-cell stimuli (concanavalin A and alloantigens) was diminished; however, B-cell proliferation to lipopolysaccharide was relatively unchanged in mice fed ethanol-containing diet. Also in ethanol-fed mice a significant decrease in the primary antibody response to sheep red blood cells but not to the T-independent antigen trinitrophenol-ficoll occurred. These data establish the murine model system as a means to define further the effect of ethanol on the immune system and host defense mechanisms.

Cerebrospinal fluid levels of somatostatin, corticotropin-releasing hormone and corticotropin in alcoholism

Reduced brain and cerebrospinal fluid (CSF) levels of somatostatin, corticotropin-releasing hormone (CRH) and corticotropin (ACTH) have been reported among neuropsychiatric patients with cognitive dysfunction. Alcoholism is a disorder in which associated neuropsychiatric disorders occur. Therefore, we compared CSF levels of somatostatin, CRH and ACTH in alcoholics (n = 100) and normal controls (n = 30). There were no significant differences between the groups in concentrations of the 3 peptides. Moreover, there were no significant correlations between concentrations of the peptides in CSF and computed tomographic measures of the size of brain ventricles. There were, however, significant correlations between CSF concentrations of CRH and ACTH and between CSF concentrations of CRH and somatostatin in both the alcoholic and control groups.

Prolonged exposure to alcohol: effect on CRF mRNA levels, and CRF- and stress-induced ACTH secretion in the rat

We have conducted studies in intact adult male rats, designed to examine the effect of a 3- or 7-day exposure to alcohol (EtOH) on the pituitary's response to corticotropin-releasing hormone (CRF) or stress, and on CRF expression in the hypothalamus. In a first series of experiments, rats exposed to EtOH vapors for 7 days had mean blood alcohol levels (BAL) of 127 +/- 12 mg%. At the end of the 7-day period, basal plasma ACTH levels were 69 +/- 10 pg/ml in control rats and 121 +/- 23 pg/ml in EtOH animals (P less than or equal to 0.01). Resting corticosterone levels were 39 +/- 11 ng/ml in control animals, and 101 +/- 24 ng/ml in EtOH rats (P less than or equal to 0.01). In all experiments described here, there was no statistical difference (P greater than 0.05) between the body weights of controls (animals kept in chambers with normal atmosphere) and EtOH-exposed animals. In control animals, the injection of 0.3-10 micrograms ovine CRF per rat caused dose-related increases in plasma ACTH levels measured 10 min later. All doses of CRF also significantly (P less than or equal to 0.01) stimulated ACTH secretion by EtOH rats, but there was no clear dose-response curve. Though EtOH-treated animals responded to the lower dose of CRF (0.3 microgram) with larger increases in plasma ACTH levels than control rats, the only statistical difference (P less than or equal to 0.01) between control and EtOH rats was observed following administration of 10 micrograms CRF, which caused a blunted response in EtOH animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Corticotropin-releasing factor is altered in brains of animals with high preference for ethanol

Ethanol administered to rats has been shown to stimulate the hypothalamic-pituitary-adrenal axis. The present study describes alterations in brain CRF neuronal systems that accompanied the voluntary high consumption of ethanol by Wistar rats presented with a free choice between 6% ethanol and tap water. Hypothalamic CRF concentrations (outside median eminence) were significantly increased in animals with a high preference for ethanol whereas concentrations of CRF in neurointermediate pituitary and medulla-pons were significantly decreased. No changes of CRF levels were evident in median eminence, frontal cortex, midbrain, thalamus, or cerebellum. Brain CRF concentrations in two strains of mice with genetically determined differential alcohol preference were measured. In ethanol-naive mice, there were documented differences in CRF concentrations, with an increase in frontal cortex levels, and a decrease in medulla-pons levels in the ethanol-preferring strain (C57BL/6J) compared to the nonpreferring strain (C3H/CRGL/2). Thus, certain brain CRF neuronal systems are preferentially affected by high ethanol consumption, and pre-existing differences in these systems may even contribute to the development of a high preference for ethanol.

Characterization of the effects of acute ethanol administration on the release of beta-endorphin peptides by the rat hypothalamus

In the present studies the direct effect of ethanol on the release of beta-endorphin by the rat hypothalamus was investigated. When various concentrations of ethanol (10-120 mM) were added into the incubation medium, it was noticed that though low concentrations of ethanol (10, 20 and 30 mM) induced a pronounced increase in the release of beta-endorphin-like peptides from the hypothalamus, high concentrations of ethanol (40, 60 and 120 mM) induced a less pronounced increase. Exposure of hypothalamus to depolarizing concentrations of potassium chloride (following washing of the ethanol), provoked a significant release of beta-endorphin-like peptides, regardless of the ethanol concentration the tissues were exposed prior to the stimulation with the potassium chloride. Chromatographic analysis of the incubation media with Sephadex-G-75 revealed that the hypothalamus released mainly beta-endorphin-sized peptides. Analysis of the beta-endorphin-sized peptides with reverse-phase high performance liquid chromatography indicated the presence of beta-endorphin-(1-31) as well as non-acetyl and acetyl beta-endorphin-(1-27). Thus ethanol exerts a biphasic effect on the release of beta-endorphin-like peptides by the rat hypothalamus, with low concentrations inducing a dose-dependent increase, reaching maximum at 20 mM ethanol, and with higher concentrations of ethanol inducing a less pronounced increase in the release of beta-endorphin-like peptides, leading to an inverted U-shaped dose response relationship of ethanol and release of beta-endorphin-like peptides from the rat hypothalamus.

Alterations in interleukin-2 utilization by T-cells from rats treated with an ethanol-containing diet

Administration of ethanol to Sprague-Dawley rats has been shown to produce a defect in lymphocyte proliferation in response to concanavalin A. Because a critical element in T-cell proliferation is the production of interleukin-2, experiments were designed to evaluate the influence of ethanol on the production and utilization of interleukin-2 by spleen cells from ethanol-treated animals. To ensure that changes in spleen cell responses to mitogenic stimulation were not simply caused by a loss of responding T cells, we tested nylon wool-nonadherent cells. The response to concanavalin A of isolated T cells from ethanol-treated rats was consistently less than that of equivalent numbers of cells from control animals. The addition of recombinant interleukin-2 to cultures of T cells did not correct the defect in proliferation to concanavalin A noted in cells from ethanol-treated rats. Further study results demonstrated that interleukin-2 production by T cells from ethanol-treated animals was equal to or greater than that by cells from animals given control diet. Blast cells recovered from 48-hr concanavalin A-stimulated spleen cell cultures from ethanol-treated animals, however, showed a decreased ability to proliferate in response to exogenous interleukin-2. Binding of 125I-interleukin-2 to blast cells resulting from concanavalin A stimulation, under conditions that detected high-affinity binding, was similar in cells from treated and control animals. These data indicate that the deficiency in proliferation of lymphocytes from ethanol-treated animals is not caused by a lack of interleukin-2 production by the T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of adrenalectomy on ethanol-associated immunosuppression

The alterations in lymphoid cell numbers and lymphocyte function due to administration of ethanol was found to be associated with high levels of circulating corticosteroids. The role of corticosteroids in the ethanol-induced alterations in the immune system was studied by administering ethanol to adrenalectomized rats. The results of these experiments showed that the ethanol-induced loss of cells from the thymus was not completely prevented by adrenalectomy and the ethanol-induced loss of cells from the spleen was not affected by adrenalectomy. Likewise the ethanol-induced decrease in antibody production to the T-cell-dependent antigen sheep erythrocytes were not affected by adrenalectomy. The ability of animals to produce antibodies of the T-cell-independent antigen, TNP-Ficoll, was not affected by ethanol regardless of whether the animals had adrenal glands or not. These data indicate that adrenal corticosteroids are responsible for some but not all of the thymic involution due to ethanol intoxication. Also, adrenalectomized rats did not show as much impairment in lymphocyte proliferation as sham adrenalectomized animals after ethanol administration. However, this loss of cells from peripheral lymphoid organs such as the spleen and the decreased ability to respond to T-cell-dependent antigens is not influenced by adrenalectomy indicating mechanisms other than corticosteroids mediate these effects of ethanol.

Mechanisms of suppression of cellular immunity induced by ethanol

Previous study findings from this laboratory and other laboratories have established that ethanol administration to experimental animals or ingestion by human beings results in many changes in the immune system. The major effort in this laboratory is the study of the mechanisms by which ethanol down-regulates the responses of thymus-derived lymphocytes. By using a rat model of ethanol intoxication we have described a defect in lymphocyte proliferation to concanavalin A. In the current report data, preliminary and definitive, are presented that show our approach to determining the mechanisms of ethanol-associated impairments in the immune system, especially the defect in lymphocyte proliferation. We have found that purified thymus-derived lymphocytes from the spleens of ethanol-treated rats have an inherent defect in their response to mitogenic stimulation. This defect is not caused by the direct effects of ethanol on the cells and probably is not caused by an inability of the cells from ethanol-treated animals to produce the lymphocyte growth factor interleukin 2. Data are also presented that indicate that corticosteroids, produced most abundantly in this model by withdrawal from ethanol, play a role in the down-regulation of the response of spleen cells to mitogenic stimulation.

Interaction of ethanol and stress with the GABA/BZ receptor in LS and SS mice

The interaction of stress and ethanol with the GABA/BZ receptor system was evaluated in LS and SS mice. The effects of two separate in vivo treatments, a 2.5 g/kg injection of ethanol or a behavioral stressor, on GABA-enhanced [3H]-FNZ binding were nearly identical in both lines of mice. A 2.5 g/kg ethanol- or stress-pretreatment resulted in increased enhancement in SS cortex, but not LS. In cerebellum, treatment effects were demonstrated in both SS and LS mice. Intraperitoneal injections of increasing doses of ethanol produced biphasic stimulation of GABA-enhanced [3H]-FNZ binding in LS brain regions, but not SS. Adrenalectomies performed one week prior to ethanol administration produced a loss of ethanol enhancement in cerebellum of both lines. However, in cortex, removal of the adrenals had no effect. The in vitro addition of 30 mM ethanol to brain preparations incubated at 37 degrees C from stressed and unstressed animals resulted in greater enhancement of binding in cortex, but not cerebellum of stressed mice. Differences in the degree of enhancement between the lines of mice were lost if the animals were stressed prior to sacrifice or if membrane preparations were incubated at 4 degrees C. The results of this study suggest that the interaction between ethanol and stress is mediated by the GABAergic system, but responses vary dependent on brain region, dose of ethanol, and degree of ethanol sensitivity.

The effect of ethanol on the biosynthesis and regulation of opioid peptides

Alcoholism and alcohol abuse are serious health problems. Alcohol is known to influence the activity of a number of biological systems, for example the hormonal and neuronal systems. One of the biological systems whose activity is greatly influenced by alcohol is the endogenous opiate system. Alcohol modifies the function of both opiate receptors and opioid peptides. In fact it has been proposed that many of the effects of ethanol are mediated by its effects on the endogenous opiate system. This review will present results from various laboratories on the effects of acute and chronic ethanol treatments on various species, and on the release, biosynthesis and post-translational processing of the endorphins, enkephalins and dynorphins, the three known families of endogenous opioid peptides. Furthermore, the effect of acute and chronic ethanol consumption on the beta-endorphin system in man, and the possible implications of the functional activity of the endogenous opiate system for the genetic predisposition to alcoholism will be discussed.

Acute and chronic ethanol treatment on beta-endorphin and catecholamine levels

The effect of acute (2.0 g/kg, intragastrically) and chronic (8.0-11.0 g/kg/day for 10 days, intragastrically) ethanol exposure on beta-endorphin levels in plasma, hypothalamus and pituitary were examined in rats. Hypothalamic and plasma catecholamines and plasma corticosterone were also measured in these animals. Plasma beta-endorphin, norepinephrine (NE) and corticosterone levels were significantly increased and dopamine (DA) was unchanged in acute and chronic ethanol-treated rats. Compared to controls, plasma epinephrine (E) levels were increased in acute ethanol-treated rats but no significant change was observed in chronic ethanol-treated rats. Plasma dopamine were significantly decreased following chronic ethanol treatment while no significant change was observed after acute treatment. In the hypothalamus, beta-endorphin and dopamine contents were increased and norepinephrine levels were reduced in response to ethanol exposure. Beta-endorphin levels were decreased significantly in the anterior pituitary and the neurointermediate lobe of the pituitary in ethanol-treated animals except in the neurointermediate lobe of the chronic ethanol-treated animals. These findings together suggest that there is an interaction between beta-endorphin, catecholamines, corticosterone and ethanol in response to acute and chronic ethanol exposure in rats.

Benzodiazepines in the treatment of alcoholism

This chapter comprises three sections that cover the main aspects of benzodiazepines and alcohol: (1) the basic pharmacology of benzodiazepines; (2) use of benzodiazepines in the treatment of withdrawal; and (3) the use of benzodiazepines in treating alcoholics. The basic studies suggest that a major site of action of alcohol may be the GABA/benzodiazepine receptor complex and that compensatory alterations in this complex may underly withdrawal. In the section on alcohol withdrawal, interactions between the GABA/benzodiazepine receptor complex, sympathetic nervous system, and hypothalamic-pituitary-adrenal axis are discussed. Use of benzodiazepines in the treatment of the alcohol withdrawal syndrome are reviewed, including the possibility that the benzodiazepines may prevent withdrawal-induced "kindling." Lastly, we review indications for, and efficacy of, benzodiazepines in long-term treatment of patients with alcoholism. Benzodiazepines are not indicated for the treatment of alcoholism. Furthermore, they have very few indications in alcoholics and their dependency-producing potency has to be appreciated when they are used in patients with alcoholism.

Ethanol differentially enhances adrenocortical response in LS and SS mice

The stimulatory effect of ethanol on the hypothalamo-pituitary-adrenal (HPA) axis was investigated in the long-sleep (LS) and short-sleep (SS) lines of mice. Plasma corticosterone concentrations peaked 30 min after IP administration of ethanol in both lines of mice. Ethanol produced dose-dependent elevations in plasma corticosterone in both LS and SS mice; however, at low doses of ethanol (0.25 to 1 g/kg) the adrenocortical response observed in LS mice was markedly greater than in SS mice. Passive immunoneutralization of circulating corticotropin releasing factor (CRF) completely abolished ethanol-induced elevation in plasma corticosterone in LS mice. CRF or ACTH (adrenocorticotropin) produced dose-dependent elevations in plasma corticosterone in the two lines of mice. Epinephrine co-administered with CRF did not potentiate the adrenocortical response obtained with CRF in either line of mice, and hexamethonium only slightly attenuated ethanol-induced elevations in plasma corticosterone in both lines of mice, suggesting that differentially elevated plasma catecholamines are not responsible for differences in ethanol-induced adrenocortical response. The results suggest that differential adrenocortical response to ethanol exhibited by LS and SS mice is due primarily to differential ethanol-induced CRF release.

Acute ethanol poisoning and the ethanol withdrawal syndrome

Ethanol, a highly lipid-soluble compound, appears to exert its effects through interactions with the cell membrane. Cell membrane alterations indirectly affect the functioning of membrane-associated proteins, which function as channels, carriers, enzymes and receptors. For example, studies suggest that ethanol exerts an effect upon the gamma-aminobutyric acid (GABA)-benzodiazepine-chloride ionophore receptor complex, thereby accounting for the biochemical and clinical similarities between ethanol, benzodiazepines and barbiturates. The patient with acute ethanol poisoning may present with symptoms ranging from slurred speech, ataxia and incoordination to coma, potentially resulting in respiratory depression and death. At blood alcohol concentrations of greater than 250 mg% (250 mg% = 250 mg/dl = 2.5 g/L = 0.250%), the patient is usually at risk of coma. Children and alcohol-naive adults may experience severe toxicity at blood alcohol concentrations less than 100 mg%, whereas alcoholics may demonstrate significant impairment only at concentrations greater than 300 mg%. Upon presentation of a patient suspected of acute ethanol poisoning, cardiovascular and respiratory stabilisation should be assured. Thiamine (vitamin B1) and then dextrose should be administered, and the blood alcohol concentration measured. Subsequent to stabilisation, alternative aetiologies for the signs and symptoms observed should be considered. There are presently no agents available for clinical use that will reverse the acute effects of ethanol. Treatment consists of supportive care and close observation until the blood alcohol concentration decreases to a non-toxic level. In the non-dependent adult, ethanol is metabolised at the rate of approximately 15 mg%/hour. Haemodialysis may be considered in cases of a severely ill child or comatose adult. Follow-up may include referral for counselling for alcohol abuse, suicide attempts, or parental neglect (in children). The ethanol withdrawal syndrome may be observed in the ethanol-dependent patient within 8 hours of the last drink, with blood alcohol concentrations in excess of 200 mg%. Symptoms consist of tremor, nausea and vomiting, increased blood pressure and heart rate, paroxysmal sweats, depression, and anxiety. Alterations in the GABA-benzodiazepine-chloride receptor complex, noradrenergic overactivity, and hypothalamic-pituitary-adrenal axis stimulation are suggested explanations for withdrawal symptomatology.(ABSTRACT TRUNCATED AT 400 WORDS)