Various Doses Of Ethanol Research Articles

Psoralea corylifolia (babchi) seeds enhance proliferation of normal human cultured melanocytes: GC–MS profiling and biological investigation

Abstract Plants are considered as a source of medicine to treat skin-related disorders since decades. Seeds of Psoralea corylifolia were used thousands of years ago for re-pigmentation in vitiligo patients especially in South Asia. It is a well-known fact that melanocytes, which are the specialized cells in the skin causes vitiligo through a series of chemical and enzymatic reactions, mainly due to the copper containing enzyme tyrosinase. Conditions associated with overproduction of melanin are termed hyperpigmentation. The treatment options are generally limited due to the complicated and slow pathogenesis of the disease. Therefore, therapeutic repigmentation modalities for the treatment of vitiligo are highly desirable. The aim of this study was to investigate the effects of various doses of ethanol and water extracts of P. corylifolia seeds on proliferation of normal human cultured melanocytes and its gas chromatography–mass spectrometry profiling.

Assessing the motivational effects of ethanol in mice using a discrete-trial current-intensity intracranial self-stimulation procedure

BackgroundAlcohol (ethanol) produces both rewarding and aversive effects, and sensitivity to these effects is associated with risk for an alcohol use disorder (AUD). Measurement of these motivational effects in animal models is an important but challenging aspect of preclinical research into the neurobiology of AUD. Here, we evaluated whether a discrete-trial current-intensity intracranial self-stimulation (ICSS) procedure can be used to assess both reward-enhancing and aversive responses to ethanol in mice. MethodsMale and female C57BL/6J mice were surgically implanted with bipolar stimulating electrodes targeting the medial forebrain bundle and trained on a discrete-trial current-intensity ICSS procedure. Mice were tested for changes in response thresholds after various doses of ethanol (0.5 g/kg-1.75 g/kg; n = 5–7 per dose), using a Latin square design. ResultsA 1 g/kg dose of ethanol produced a significant reward-enhancement (i.e., lowered response thresholds), whereas a 1.75 g/kg dose produced an aversive effect (elevated response thresholds). Ethanol doses from 1 to 1.75 g/kg increased response latencies as compared to saline treatment. ConclusionsThe discrete-trial current-intensity ICSS procedure is an effective assay for measuring both reward-enhancing responses to ethanol as well as aversive responses in the same animal. This should prove to be a useful tool for assessing the effects of experimental manipulations on the motivational effects of ethanol in mice.

Re-evaluation of the reward comparison hypothesis for alcohol abuse.

This study examined whether various doses of ethanol induced reward or aversion and then evaluated Grigson's reward comparison hypothesis (1997). Rats were given a 0.1% saccharin solution (conditioned stimulus 1 [CS1]) 15min prior to administration of a 0, 0.05, 0.125, 0.20, 0.35, or 0.50g/kg dose of ethanol (unconditioned stimulus [US]). The rats were then exposed to a paired compartment (CS2) for 30min. The low dose of 0.05g/kg ethanol did not induce conditioned suppression (i.e., conditioned taste aversion [CTA]) or conditioned place preference (CPP). The dose of 0.125g/kg ethanol induced CPP but not CTA. High doses of ethanol, including 0.35g/kg and 0.50g/kg, produced CTA but not CPP. The middle dose of 0.20g/kg ethanol simultaneously induced CTA and CPP. As a result, the reward comparison hypothesis cannot explain the present finding that the middle dose of ethanol induced CTA and CPP. Meanwhile, the high doses of ethanol induced motivationally aversive CTA but not rewarding CPP. The reward comparison hypothesis should be updated further.

A new view of alcohol metabolism and alcoholism--role of the high-Km Class III alcohol dehydrogenase (ADH3).

The conventional view is that alcohol metabolism is carried out by ADH1 (Class I) in the liver. However, it has been suggested that another pathway plays an important role in alcohol metabolism, especially when the level of blood ethanol is high or when drinking is chronic. Over the past three decades, vigorous attempts to identify the enzyme responsible for the non-ADH1 pathway have focused on the microsomal ethanol oxidizing system (MEOS) and catalase, but have failed to clarify their roles in systemic alcohol metabolism. Recently, using ADH3-null mutant mice, we demonstrated that ADH3 (Class III), which has a high Km and is a ubiquitous enzyme of ancient origin, contributes to systemic alcohol metabolism in a dose-dependent manner, thereby diminishing acute alcohol intoxication. Although the activity of ADH3 toward ethanol is usually low in vitro due to its very high Km, the catalytic efficiency (kcat/Km) is markedly enhanced when the solution hydrophobicity of the reaction medium increases. Activation of ADH3 by increasing hydrophobicity should also occur in liver cells; a cytoplasmic solution of mouse liver cells was shown to be much more hydrophobic than a buffer solution when using Nile red as a hydrophobicity probe. When various doses of ethanol are administered to mice, liver ADH3 activity is dynamically regulated through induction or kinetic activation, while ADH1 activity is markedly lower at high doses (3–5 g/kg). These data suggest that ADH3 plays a dynamic role in alcohol metabolism, either collaborating with ADH1 or compensating for the reduced role of ADH1. A complex two-ADH model that ascribes total liver ADH activity to both ADH1 and ADH3 explains the dose-dependent changes in the pharmacokinetic parameters (β, CLT, AUC) of blood ethanol very well, suggesting that alcohol metabolism in mice is primarily governed by these two ADHs. In patients with alcoholic liver disease, liver ADH3 activity increases, while ADH1 activity decreases, as alcohol intake increases. Furthermore, ADH3 is induced in damaged cells that have greater hydrophobicity, whereas ADH1 activity is lower when there is severe liver disease. These data suggest that chronic binge drinking and the resulting liver disease shifts the key enzyme in alcohol metabolism from low-Km ADH1 to high-Km ADH3, thereby reducing the rate of alcohol metabolism. The interdependent increase in the ADH3/ADH1 activity ratio and AUC may be a factor in the development of alcoholic liver disease. However, the adaptive increase in ADH3 sustains alcohol metabolism, even in patients with alcoholic liver cirrhosis, which makes it possible for them to drink themselves to death. Thus, the regulation of ADH3 activity may be important in preventing alcoholism development.

Effect of the allelic variants of aldehyde dehydrogenase ALDH2*2 and alcohol dehydrogenase ADH1B*2 on blood acetaldehyde concentrations

Alcoholism is a complex behavioural disorder. Molecular genetics studies have identified numerous candidate genes associated with alcoholism. It is crucial to verify the disease susceptibility genes by correlating the pinpointed allelic variations to the causal phenotypes. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the principal enzymes responsible for ethanol metabolism in humans. Both ADH and ALDH exhibit functional polymorphisms among racial populations; these polymorphisms have been shown to be the important genetic determinants in ethanol metabolism and alcoholism. Here, we briefly review recent advances in genomic studies of human ADH/ALDH families and alcoholism, with an emphasis on the pharmacogenetic consequences of venous blood acetaldehyde in the different ALDH2 genotypes following the intake of various doses of ethanol. This paper illustrates a paradigmatic example of phenotypic verifications in a protective disease gene for substance abuse.

Effects of acute ethanol on opioid peptide release in the central amygdala: an in vivo microdialysis study

There is experimental evidence that indicates that the endogenous opioid system of the central nucleus of the amygdala (CeA) may mediate some of the reinforcing effects of ethanol. However, the precise interactions of ethanol with the endogenous opioid system at the level of the CeA have not been investigated. The aim of the current study was to investigate the hypothesis that acute systemic ethanol administration will increase the release of endogenous opioid peptides at the level of the CeA in a time- and dose-dependent manner. Rats were implanted with a unilateral guide cannula to aim microdialysis probes at the CeA. Intraperitoneal injections of saline and various doses of ethanol (0.8, 1.6, 2.0, 2.4, and 2.8 g ethanol/kg body weight) were administered to the rats. Dialysate samples were collected at 30-min intervals at distinct time points prior to and following treatment. Radioimmunoassays specific for beta-endorphin, met-enkephalin, and dynorphin A1-8 were used to determine the effect of ethanol on the content of the opioid peptides in the dialysate. We report that the 2.8-g/kg dose of ethanol induced a long-lasting increase in beta-endorphin release from 60 min onwards following administration and, later, an ongoing increase in dynorphin A1-8 release. None of the ethanol doses tested elicited significant changes in dialysate met-enkephalin content compared to the saline treatment. Acute systemic ethanol administration induced a dose- and time-dependent increase in beta-endorphin and dynorphin A1-8 release at the level of the CeA, which may be involved in ethanol consumption.

The effects of nicotine on ethanol-induced conditioned taste aversions in Long–Evans rats

Overall drug acceptability is thought to be a function of the balance between its rewarding and aversive effects, the latter of which is reportedly affected by polydrug use. Given that nicotine and alcohol are commonly co-used, the present experiments sought to assess nicotine's impact on ethanol's aversive effects within a conditioned taste aversion design. Experiment 1 examined various doses of nicotine (0, 0.4, 0.8, 1.2 mg/kg) to determine a behaviorally active dose, and experiment 2 examined various doses of ethanol (0, 0.5, 1.0, 1.5 g/kg) to determine a dose that produced intermediate aversions. Experiment 3 then examined the aversive effects of nicotine (0.8 mg/kg) and ethanol (1.0 g/kg) alone and in combination. Additionally, nicotine's effects on blood alcohol concentrations (BAC) and ethanol-induced hypothermia were examined. Nicotine and ethanol combined produced aversions significantly greater than those produced by either drug alone or the summed aversive effects of the individual compounds. These effects were unrelated to changes in BAC, but nicotine and ethanol combined produced a prolonged hypothermic effect which may contribute to the increased aversions induced by the combination. These data demonstrate that nicotine may interact with ethanol, increasing ethanol's aversive effects. Although the rewarding effects of concurrently administered nicotine and ethanol were not assessed, these data do indicate that the reported high incidence of nicotine and ethanol co-use is unlikely due to reductions in the aversiveness of ethanol with concurrently administered nicotine. It is more likely attributable to nicotine-related changes in ethanol's rewarding effects.

Dissociation Between the Time Course of Ethanol and Extracellular Dopamine Concentrations in the Nucleus Accumbens After a Single Intraperitoneal Injection

Dopamine release in the nucleus accumbens has been linked to the reinforcing effects of ethanol, but the time course or relationship of this response to ethanol concentrations in the brain has not been studied. Various doses of ethanol (0-2.0 g/kg) were administered intraperitoneally to male Sprague Dawley rats, and dopamine and ethanol were simultaneously analyzed in dialysate samples from the nucleus accumbens. A separate study to compare the ethanol-induced dopamine response in male and female rats was carried out by using a 1 g/kg intraperitoneal dose of ethanol. In male rats, 1 and 2 g/kg ethanol significantly increased dialysate dopamine by 40% over basal, whereas 0.25 and 0.5 g/kg ethanol produced a nonsignificant 20% increase. Dialysate ethanol concentrations exhibited a curvilinear decline after reaching peak levels for the lower doses but showed a linear decrease after 1 and 2 g/kg. There was a dissociation between the time courses of extracellular dopamine and ethanol after 1 and 2 g/kg ethanol treatment. The dopamine response returned to basal within 90 min, whereas the ethanol concentrations remained elevated. In a separate study that compared male and female rats, the ratio of the dopamine response over basal to the dialysate ethanol concentrations was significantly decreased at 60 min after an injection of 1 g/kg. However, there were no differences between males and females. The dissociation between dopamine and ethanol levels may reflect the development of acute tolerance to ethanol-induced dopamine release in the nucleus accumbens within the time course of a single acute injection. Given the strong links between dopamine and ethanol reinforcement, our findings may be relevant for understanding the time course of ethanol's reinforcing effects in vivo.

EFFECTS OF ETHANOL ON PLASMA CHLOROQUINE, ARGININE VASOPRESSIN (AVP) CONCENTRATIONS AND RENAL HYDRO-ELECTROLYTE HANDLING IN THE RAT

Current evidence in literature suggests that acute effects of either chloroquine or ethanol on kidney function partly depend on influencing plasma concentrations of arginine vasopressin (AVP). Therefore, the goal of the current study was to explore the effects of chloroquine and/or various doses of ethanol on plasma AVP levels and associated effects on renal hydro-electrolyte handling. Separate groups of male anaesthetized Sprague-Dawley rats were placed on a continuous jugular infusion of 0.077M NaCl at 150μL/min−1. After 3h equilibration period, consecutive 20min urine collections were made over the subsequent 4h of 1h control, 1h 20min treatment and 1h 40min postequilibration periods for measurements of urine flow and Na+ and K+ excretion rates. Chloroquine (0.06μg/min−1) and/or ethanol at either 2.4, 6, 18 or 24μg/min−1were added to the infusate during the treatment period. Trunk blood was collected after the treatment period from parallel groups for AVP, ethanol and chloroquine measurements. Vehicle infused animals acted as control animals.Infusion of ethanol at low rate of 2.4μg/min−1 increased Na+ excretion rates, but high rates (6 -24μg/min−1) did not elicit such effects. Plasma ethanol concentrations were undetectable following administration of ethanol alone at 2.4 or 6μg/min−1. However, ethanols were measurable following co-infusion of chloroquine and ethanol at 6μg/min−1 (6±1 mg/dL−1). Concurrent chloroquine and ethanol (24μg/min−1) administration elevated plasma ethanol concentrations by 26% by comparison with that of ethanol alone at the same dose. Chloroquine and ethanol infusion at all doses significantly (p < 0.01) increased plasma chloroquine concentrations. Intravenous infusion of ethanol increased plasma AVP concentrations in a dose-dependent manner. The observations of this study suggest that acute ethanol increases plasma AVP levels in a dose-dependent manner to affect hydro-electrolyte balance.

Ethanol concentrations approaching minimum alveolar anesthetic concentration are required to suppress learning in a fear-potentiated startle paradigm in rats.

We previously demonstrated that desflurane and two nonimmobilizers dose-dependently decrease learning and memory in rats. This suggests that although they do not suppress movement in response to noxious stimuli, nonimmobilizers act like inhaled anesthetics in their effects on learning and memory. Like most conventional anesthetics, nonimmobilizers have a greater affinity for lipid than for aqueous phases. In the present study, we examined the effect of ethanol on learning and memory to test the hypothesis that a large part of the capacity of anesthetics to affect learning depends on an action on a lipid (nonpolar) phase. Unlike volatile anesthetics and nonimmobilizers, ethanol has a greater affinity for water than for lipids. Thus, if our hypothesis is correct, ethanol should be relatively less potent in its suppression of memory. Rats receiving various doses of ethanol were conditioned to fear a light followed by a footshock. Fear conditioning to the light was subsequently assessed by measurement of potentiation of the acoustic startle reflex in the presence, compared with the absence, of light. Ethanol up to 0.54 minimum alveolar anesthetic concentration (MAC) did not abolish fear, but 0.82 MAC ethanol did abolish learning. Expressed as a fraction of MAC or predicted MAC, ethanol is less potent than desflurane or the nonimmobilizer 1,2-dichlorohexafluorocyclobutane in suppressing learning. This finding is consistent with the hypothesis that the capacity of anesthetics and nonimmobilizers to impair learning and memory depends mostly on an action at a nonpolar site. Abolition of learning and memory is an important property of inhaled anesthetics. This effect primarily results from an action at a lipid (nonpolar) site, rather than a polar site or a water-lipid interface.

Forskolin Delays the Ethanol-Induced Desensitization of Hypothalamic β-Endorphin Neurons in Primary Cultures.

Ethanol and its metabolite acetaldehyde have been shown to stimulate immunoreactive β-endorphin (IR-β-EP) secretion from hypothalamic neurons in primary cultures. Also, chronic ethanol and acetaldehyde have been shown to cause the development of tolerance and desensitization of these neurons. In this study, we determined some of the cellular events leading to desensitization of the function of β-endorphin (p-EP) Secretory neurons. The fetal hypothalamic cells were treated with various doses of ethanol (W and 50 mM) or acetaldehyde (6.25,12.5, and 25 mM) for 6 hr or treated with these drugs at 12 hr intervals for 72 hr. Determination of IR-β-EP concentrations in the media revealed that ethanol increased IR-β-EP secretion from these cultures for 12 hr; after this period, the cultured cells did not respond to ethanol. Acetaldehyde stimulated IR-β-EP secretion from this culture for a period of 48 hr, but the IR-β-EP secretory response to acetaldehyde reduced gradually with time during the first 48-hr period and reached the basal level at 72 hr. The desensitization of β-EP neurons 12 hr after treatment with alcohol did not seem to be related to the loss of viable cells, because chronic ethanol exposures did not produce any effect on cell viability. However, reduced IR- β-EP secretory response to acetaldehyde with time was associated with the time-dependent increase in cell death. Pretreatment of cultures with a cAMP analog, forskolin, increased the activity of functional β-EP neurons and delayed the ethanol desensitization effects on these neurons. Pretreatment of forskolin did not delay the acetaldehyde desensitization of β-EP neurons, but protected these cells from acetaldehyde toxicity. These results suggest that (i) chronic treatment with ethanol desensitizes β-EP-secreting neurons due to reduced cellular functions and (ii) chronic acetaldehyde reduces β-EP neurotransmission due to cell death. Furthermore, data suggest for the first time that cAMP pretreatments delay the ethanolinduced desensitization of opioid neurons and partly protect against the neurotoxic action of acetaldehyde on opioid neurons.

Forskolin Delays the Ethanol-Induced Desensitization of Hypothalamic beta-Endorphin Neurons in Primary Cultures

Ethanol and its metabolite acetaldehyde have been shown to stimulate immunoreactive beta-endorphin (IR-beta-EP) secretion from hypothalamic neurons in primary cultures. Also, chronic ethanol and acetal-dehyde have been shown to cause the development of tolerance and desensitization of these neurons. In this study, we determined some of the cellular events leading to desensitization of the function of beta-endorphin (beta-EP) secretory neurons. The fetal hypothalamic cells were treated with various doses of ethanol (25 and 50 mM) or acetaldehyde (6.25, 12.5, and 25 mM) for 6 hr or treated with these drugs at 12 hr intervals for 72 hr. Determination of IR-beta-EP concentrations in the media revealed that ethanol increased IR-beta-EP secretion from these cultures for 12 hr, after this period, the cultured cells did not respond to ethanol. Acetaldehyde stimulated IR-beta-EP secretion from this culture for a period of 48 hr, but the IR-beta-EP secretory response to acetaldehyde reduced gradually with time during the first 48-hr period and reached the basal level at 72 hr. The desensitization of beta-EP neurons 12 hr after treatment with alcohol did not seem to be related to the loss of viable cells, because chronic ethanol exposures did not produce any effect on cell viability. However, reduced IR- beta-EP secretory response to acetaldehyde with time was associated with the time-dependent increase in cell death. Pretreatment of cultures with a cAMP analog, forskolin, increased the activity of functional beta-EP neurons and delayed the ethanol desensitization effects on these neurons. Pretreatment of forskolin did not delay the acetaldehyde desensitization of beta-EP neurons, but protected these cells from acetaldehyde toxicity. These results suggest that (i) chronic treatment with ethanol desensitizes beta-EP-secreting neurons due to reduced cellular functions and (ii) chronic acetaldehyde reduces beta-EP neurotransmission due to cell death. Furthermore, data suggest for the first time that cAMP pretreatments delay the ethanol-induced desensitization of opioid neurons and partly protect against the neurotoxic action of acetaldehyde on opioid neurons.

Features of DNA oligonucleosomal fragmentation in human tumor cell lines and its detection by flow cytometry: utility and limitations.

Cultured HL‐60, HeLa S3 and WiDr cells were treated with various doses of ethanol, then subjected to flow cytometry and gel electrophoresis of cellular DNA. On electrophoresis of DNA from HL‐60 cells treated with 0.5 or 1.0 mM ethanol, a ladder pattern was recognized after 3 h. At higher doses of ethanol (2.0 and 5.0 mM), a smear pattern resulted. On flow cytometry, however, A0 cells (lower fluorescence level than G0+ G1 cells) were noted from 0.5 to 5,0 mM ethanol. The observation of A0 cells at higher doses indicated loss of DNA after random DNA degradation. HeLa S3 and WiDr cells were partially detached from flasks after administration of ethanol and separated into adherent and non‐adherent categories. In DNA from non‐adherent HeLa S3 cells treated with 0.5 mM ethanol, a ladder pattern was observed after 24 h. On flow cytometry, prior to the appearance of A0 cells, an accumulation in the G2+M‐phase became obvious after 3 h. Increased mitotic indices indicated that this phenomenon was due to M‐phase arrest. Adherent HeLa S3 cells showed no DNA Oligonucleosomal fragmentation or A0 cells. These findings indicate that detection of A0 cells by flow cytometry is not proof of cell death by DNA Oligonucleosomal fragmentation.

Effects of chronic alcohol on immunoreactive beta-endorphin secretion from hypothalamic neurons in primary cultures: evidence for alcohol tolerance, withdrawal, and sensitization responses.

Endogenous opioid peptides are known to be involved in the alcohol tolerance and dependence following alcohol abuse. However, the cellular mechanisms involved in the ethanol tolerance and dependence are not well established. We have previously shown that low concentrations of ethanol stimulate immunoreactive beta-endorphin (IR-beta-EP) release from the cultured hypothalamic neurons and that chronic ethanol exposure desensitizes these neurons to ethanol challenges. In this study, we determined the IR-beta-EP response to increasing doses of ethanol during the desensitizing phase of moderate ethanol doses to test whether the cultured IR-beta-EP-secreting neurons develop tolerance to ethanol following constant exposure. We also determined IR-beta-EP responses following withdrawal from chronic ethanol challenge and compared the IR-beta-EP secretory response to various doses of ethanol in ethanol-naive and ethanol-preexposed cultures. The IR-beta-EP responses to increasing doses of ethanol (50-150 mM) were markedly reduced in the cultures preexposed to a 50 mM dose of ethanol when compared with those that were naive to ethanol. The ethanol-exposed cultures showed hypersecretion of IR-beta-EP after removal from 48 hr of constant ethanol, as compared with ethanol-naive cultures. When ethanol-preexposed cultures were challenged with various doses of ethanol 4 days after ethanol withdrawal, the cultures showed higher IR-beta-EP secretory responses than did the ethanol-naive cultures. These data suggest that IR-beta-EP secretory neurons in primary cultures develop tolerance to chronic ethanol, show withdrawal response after removal of chronic ethanol exposure, and develop sensitization following repeated ethanol challenges.

Influence of Thiamine on the Behavioral Sensitivity to Ethanol

Changes in sensitivity to ethanol's rate-decreasing effects on operant performance were examined in control rats and cohorts that received diet-induced or diet+pyrithiamine-induced thiamine deficiency. Seven groups of male Sprague-Dawley rats (12 rats/group) were trained in a 5-cycle lever-press operant task under a fixed-ratio 30 schedule of food reinforcement. Once trained to maintain consistent operant performance across all 5 cycles, each rat was tested with various doses of ethanol injected at the beginning of each time-out cycle. Each group of rats demonstrated equivalent saline baseline operant performance and ED50 for ethanol's rate-suppressing effects. Training sessions were suspended and rats received either a short- (9 days) or long-term (5-week) exposure to regular rat chow diet or thiamine-deficient diet, and received either saline or pyrithiamine injections in a 2 x 2 design. Three additional control groups were maintained on a regular rat chow diet and received supplemental injections of either thiamine+pyrithiamine injections, thiamine+saline injections, or saline+pyrithiamine injections. The controlled diet phase continued until the development of overt signs of thiamine deficiency, at which time thiamine supplements were administered for 4 days. In phase 3, all rats were retrained in the operant task and a second ethanol dose-effect function was generated. A history of thiamine deficiency and recovery failed to shift the behavioral dose-effect functions significantly for ethanol and their associated blood alcohol curves. Most interestingly, significant behavioral sensitization to ethanol's rate suppressant effects was demonstrated in the two control groups of rats receiving regular rat chow diet in combination with supplemental injections of thiamine and either saline or pyrithiamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Guidelines for estimating the amount of alcohol consumed from a single measurement of blood alcohol concentration: re-evaluation of Widmark's equation

This article deals with the pharmacokinetics of ethanol and the reliability of estimating the amount of alcohol ingested from a single measurement of a person's blood alcohol concentration (BAC). Blood alcohol curves were plotted for 108 male subjects after they drank various doses of ethanol (0.51–0.85 g/kg body weight). The rate of disappearance of ethanol from the blood (β-slope) and the apparent volume of distribution of ethanol (Widmark's rho factor, ϱ) were calculated for each subject; the mean β-slope was 13.3 mg/dl/h (SD = 2.0), and the mean ϱ factor was 0.689 l/kg (SD = 0.061). The value of β increased slightly with increasing dose of alcohol ( P < 0.05). The blood alcohol parameters β and ϱ were negatively correlated (r = −0.135). The BACs measured at 2 h and 5 h post-drinking were used to estimate the amount of alcohol each subject had consumed according to the method proposed by Widmark [1]. The mean differences (estimated-actual) and the ±95% limits of agreement were −0.72 g (± 12), and 2.2 (± 15), for the 2 h and 5 h BAC values, respectively. A method based on error propagation was used to derive the 95% limits of uncertainty in the amount of alcohol ingested. On the basis of a single measurement of BAC, we could estimate the amount of alcohol ingested within ±20%.

Cyclic AMP and ethanol interact to control apoptosis and differentiation in hypothalamic beta-endorphin neurons.

In this study we have determined the role of cyclic AMP on the function and differentiation of beta-endorphin (beta-EP) neurons in rat fetal hypothalamic cell cultures. Addition of Bt2cAMP or the cAMP elevating agent, forskolin, in cultures, dose and time dependently increased beta-endorphin secretion. The increased beta-EP secretion after Bt2cAMP or forskolin treatment was associated with proopiomelanocortin gene expression, enhanced neurite growth, and increased neuronal viability. Determination of internucleosomal cleavage of DNA by agarose gel electrophoresis revealed that apoptosis occurred in hypothalamic neurons during the first 6-8 days in culture. Addition of Bt2cAMP during this developmental period inhibited DNA degradation in hypothalamic neurons. Furthermore, incubation with various doses of ethanol, which is known to reduce intracellular levels of Bt2cAMP, increased DNA degradation in these cells. Ethanol-induced DNA degradation was blocked by concomitant incubation with Bt2cAMP. Histochemical identification of apoptotic cells following ethanol and Bt2cAMP treatments further revealed that apoptosis occurred in beta-EP neurons during the developmental period, and that ethanol increased and Bt2cAMP reduced apoptotic beta-EP cell numbers. These results suggest that ethanol neurotoxicity on beta-EP neurons during early neuronal differentiation involves an apoptotic process and that the cAMP signaling system plays an important role in controlling apoptosis and differentiation of the beta-EP neuronal system.

Motivational properties of ethanol in mice selectively bred for ethanol-induced locomotor differences.

Ethanol-induced locomotor stimulation has been proposed to be positively correlated with the rewarding effects of ethanol (Wise and Bozarth 1987). The present experiments provided a test of this hypothesis using a genetic model. Three behavioral indices of the motivational effects of ethanol (drinking, taste conditioning, place conditioning) were examined in mice from two independent FAST lines, selectively bred for sensitivity to ethanol-induced locomotor stimulation, and mice from two independent SLOW lines, selectively bred for insensitivity to ethanol-induced locomotor stimulation. In a single-bottle procedure, mice were allowed access to drinking tubes containing ethanol in a concentration (1-12% v/v) that increased over 24 consecutive days. FAST mice consumed greater amounts of ethanol solution. In a two-bottle procedure, mice were allowed access to tubes containing water or various concentrations of ethanol (2-8% v/v) over 6 days. FAST mice generally showed greater preference for ethanol solutions than SLOW mice. In a conditioned taste aversion procedure, mice received access to saccharin solution followed by injection of 2.5 g/kg ethanol (IP). SLOW mice developed aversion to the saccharin flavor more readily than FAST mice. In a series of place conditioning experiments, tactile stimuli were paired with various doses of ethanol (0.8-2.0 g/kg). During conditioning, FAST mice showed locomotor stimulation after 1.0, 1.2 and 2.0 g/kg ethanol while SLOW mice did not. During testing, mice conditioned with 1.2 g/kg and 2.0 g/kg ethanol showed conditioned place preference, but there were no line differences in magnitude of preference. These results indicate that genetic selection for sensitivity to ethanol-stimulated activity has resulted in genetic differences in ethanol drinking and ethanol-induced conditioned taste aversion but not ethanol-induced conditioned place preference. Overall, these data provide mixed support for the psychomotor stimulant theory of addiction.

Genetic selection alters thermoregulatory response to ethanol

The present study examined the effect of ethanol on the regulated temperature of two lines of mice selected in replicate for a smaller (HOT1 and HOT2) or greater (COLD1 and COLD2) decline in rectal temperature after IP ethanol. Mice were implanted with indwelling telemetry devices for remote monitoring of internal temperature and trained in a temperature gradient (8–40°C). Both internal and selected temperature were tracked and recorded with a computer after injections of NaCl or various doses of ethanol. All animals responded similarly to control injections, with a transient rise in body temperature. After an effective dose of ethanol, mice showed clear evidence of a regulated decline in body temperature, as evidenced by selection of low temperatures in the gradient at the same time internal temperatures were falling. COLD mice were more sensitive than HOT mice; this was apparent in both replicates of the selected lines, indicating that a difference in the CNS regulator of body temperature has been selected for in these animals.

Acute and chronic ethanol tolerance: operant behaviour in naive and ethanol tolerant rats.

The relationship between tolerance to ethanol and acute tolerance to ethanol was examined. One group of rats was given 1.8 g/kg ethanol, and another group was administered 18 ml/kg saline for 26 days after sessions. Animals responded under a fixed ratio ten (FR-10) schedule of food reinforcement. Thereafter, various doses of ethanol (1.3-2.5 g/kg) were examined to assess the influence of the ethanol treatment on the expression of acute tolerance. Acute tolerance was assessed by comparing the performance at equal concentrations of ethanol on the ascending and the descending limbs of the ethanol concentration curve. This was achieved by varying the time between behavioural tests since ethanol administration. Ethanol concentrations were estimated using a rebreathed air procedure. Equal concentrations of ethanol were achieved with doses of i) 1.3 g/kg (10 min post-injection, PI), and 1.8 g/kg (60 min PI), as well as with doses of ii) 2.0 g/kg (10 min PI), and 2.5 g/kg (60 min PI). Acute tolerance was demonstrated for the initially ethanol naive animals. For the animals given ethanol chronically, only doses of ethanol higher than the chronically administered dose produced evidence for acute tolerance. When the chronically dosed animals had been off ethanol for 67 days, there was evidence for acute tolerance. The present data add to the generality of the acute ethanol tolerance phenomenon, and emphasize both the appearance as well as the loss of tolerance for this effect.