Reversal of ethanol intoxication in humans: an assessment of the efficacy of L-dopa, aminophylline, and ephedrine

Determination of free acetaldehyde in total blood for investigating the effect of aspartate on metabolism of alcohol in mice

To explore the effect of sodium L-aspartate monohydrate (aspartate) as a NAD+ regenerating agent for acetaldehyde in alcohol metabolism, a simple HPLC method has been developed for the measurement of free acetaldehyde in total mice blood digested with alcohol and aspartate. The blood samples were collected in EDTA Vacutainer tubes, and treated with 2,4-dinitrophenylhydrazine (DNP hydrazine) reagent in total blood. Acetaldehyde DNP hydrazone was extracted from total blood and analyzed by HPLC using an Ultrasphere ODS column. The compounds were separated using acetonitrile-water (50:50, v/v) as mobile phase and detected at 356 nm. The detection limit for acetaldehyde DNP hydrazone was 0.1 ppm. A blank determination was carried out for each analysis and subtracted from the results. The amount of acetaldehyde in blood has been determined as a function of time lapse after sole alcohol administration and aspartate ingestion followed by alcohol administration, respectively. This comparative analysis demonstrates that the ingestion of aspartate before the administration of alcohol dramatically decreases the aldehyde level in blood, and aspartate may be utilized as a prospective antagonist for acceleration of ethanol metabolism and prevention of acetaldehyde toxicity.

Effects of beta-phenylethylamine on locomotor activity, body temperature and ethanol blood concentrations during acute ethanol intoxication

Beta-phenylethylamine (PEA) is an endogenous amine which is metabolised by MAO B. The function of this enzyme is known to be modified by ethanol so we have studied the interactions of PEA with ethanol. Rectal temperatures of rats were determined and animals pretreated with ethanol (2.5 g kg-1 IP) 90 min before PEA 20, 40, 100 mg kg-1 IP). Spontaneous locomotor activity (SLA) was then recorded, for 30 min, temperatures redetermined and blood ethanol levels evaluated. PEA increased SLA but did not alter rectal temperatures, and at 40 mg kg-1 it not only attenuated ethanol hypothermia and blood levels but also modified ethanol hypomotility. The highest dose of PEA (100 mg kg-1) decreased blood ethanol concentration and sedation but did not counteract the hypothermia. Thus PEA increased ethanol clearance, though the underlying mechanism is not totally clear. This finding is discussed in relation to its catecholaminergic and enzyme inducing characteristics.

Apomorphine increases ethanol discrimination

Rats were trained to discriminate between the stimulus properties of 600 mg/kg ethanol and saline in a two-lever, food-motivated operant task. Once trained, rats showed a dose-related decrease in discriminative performance with lower ethanol doses and analysis of the dose-response curve indicated an ED50 of 372 mg/kg. Pretreatment with 0.16 mg/kg apomorphine produced increased discriminative performance at each ethanol dose and the combination generated a dose-response curve parallel to ethanol administered alone with an ED50 of 232 mg/kg. This significant shift to the left of the ethanol dose-response curve after apomorphine administration is discussed in relation to dopaminergic neuronal systems and the clinical use of apomorphine alcoholics.

Failure of amantadine and bromocriptine to counteract alcoholic inebriation in man

Oral amantadine 100 mg and bromocriptine 2.5 + 2.5 mg, alone and in combination with ethanol (1 g/kg), were investigated in two placebo-controlled, double-blind and cross-over trials. In the first trial the psychomotor effects of amantadine and bromocriptine were compared to those of placebo, and in the second trial ethanol was added to the treatment. Bromocriptine lowered serum prolactin levels, thus confirming its absorption. Amantadine and bromocriptine alone had no psychomotor effects but unpleasant sensations, nausea and dizziness were reported after bromocriptine. Ethanol impaired performance in terms of impaired coordinative and reactive skills, lowered tapping speed, prolonged critical flicker interval and reduced gaze nystagmus angle (P less than 0.05 to 0.001; two-way ANOVA). Subjectively, ethanol induced mental slowness, clumsiness and impairment of performance (P less than 0.05 to 0.001). Amantadine and bromocriptine failed to counteract any of these ethanol-induced changes. It is concluded that in man, an acute dopaminergic activation by amantadine or bromocriptine does not significantly modify the psychomotor effects of ethanol.

Zimelidine effects on memory impairments produced by ethanol

Zimelidine, a relatively specific 5-hydroxytryptamine reuptake blocker, attenuates the impairing effects of ethanol on learning and memory. The findings provide a potential basis for treatment of ethanol-related disorders and also points to the role of the serotonin system in mediating aspects of information processing in man.

Interaction of apomorphine and amantadine with ethanol in men

Male moderate drinkers (n = 12) drank ethanol (0.8 g/kg) and then ingested one of the following: apomorphine (5 mg), amantadine (200 mg), or placebo. Subjects were tested on a battery of physiological and behavioral measures using a double-blind, within-subjects, crossover design. Postethanol ingestion of apomorphine significantly increased ethanol's effect on 3 out of the 8 measures employed (divided attention, objective and subjective inebriation ratings) without significantly altering blood ethanol concentrations or the rate of blood ethanol decline. There was no indication that apomorphine antagonized ethanol's effects. In contrast to reports indicating that amantadine antagonized ethanol depression in rodents, amantadine did not significantly alter the degree of ethanol intoxication in humans. The increase in intoxication induced by apomorphine supports suggestions that dopaminergic systems may be involved in mediating ethanol intoxication and that the sobering effect of catecholamine-augmenting drugs results from noradrenergic, rather than combined noradrenergic and dopaminergic, stimulation. Further studies are necessary to elucidate the role of pre- and postsynaptic dopaminergic receptors in mediating these effects.

Failure of TRH and ORG 2766 hexapeptide to counteract alcoholic inebriation in man

The actions and interactions of alcohol (1.5 g/kg) and two stimulant peptides were investigated in healthy volunteers. Double blind and cross over studies in 8 subjects, at one-week intervals, revealed that ORG 2766 (5 or 20 mg i.m.) and particularly TRH (10 micrograms/kg i.v.) enhanced rather than antagonized alcohol-induced inebriation. The interactions were associated with elevated breath alcohol concentrations. Similar studies with 8 other subjects showed that peptides given in combination with a non-alcoholic drink tended to impair performance assessed as various psychophysiological variables. However, ORG 2766 5 mg was subjectively rated as producing a feeling of improved performance.

Alcohol intake and ethanol intoxication in the rate: effect of a 6-OHDA-induced lesion of the ascending noradrenaline pathways

The ascending noradrenaline (NA) pathways were lesioned by injecting 6-hydroxydopamine (6-OHDA) 16 micrograms/4 microliters bilaterally into the posterior mesencephalon in male Long Evans rats. Another group of rats was pretreated with protriptyline (25 mg/kg), a NA uptake blocking agent, 15 min before they received the intracerebral injections of 6-OHDA. The controls received the vehicle only. Spectrofluorimetric determination of the catecholamine concentrations in various parts of the brain revealed a marked degeneration of the ascending NA systems in the group receiving 6-OHDA. Unexpectedly, the DA systems were also affected by the 6-OHDA treatments. Three weeks after the operation the 6-OHDA group showed a transient increase in ethanol intake. In the tilting-plane test, ethanol (2 g/kg. i.p.) impaired the performance of the 6-OHDA-treated rats significantly more than that of the controls. In contrast, the hypothermic effect of ethanol (4 g/kg, i.p.) was significantly smaller in the lesioned rats. Furthermore, the catecholamine levels in various parts of the brain could be significantly correlated with both the extent of ethanol intoxication and the hypothermia. However, the duration of ethanol-induced narcosis (4 g/kg, i.p.) was affected by the present treatments. These results give further support for the view that the central NA neurons are important in the control of ethanol intake, and that they are involved in the expression of the acute effects of ethanol administration.