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The present paper summarizes the preclinical and clinical studies conducted to define the “anti-alcohol” pharmacological profile of the prototypic GABAB receptor agonist, baclofen, and its therapeutic potential for treatment of alcohol use disorder (AUD). Numerous studies have reported baclofen-induced suppression of alcohol drinking (including relapse- and binge-like drinking) and alcohol reinforcing, motivational, stimulating, and rewarding properties in rodents and monkeys. The majority of clinical surveys conducted to date – including case reports, retrospective chart reviews, and randomized placebo-controlled studies – suggest the ability of baclofen to suppress alcohol consumption, craving for alcohol, and alcohol withdrawal symptomatology in alcohol-dependent patients. The recent identification of a positive allosteric modulatory binding site, together with the synthesis of in vivo effective ligands, represents a novel, and likely more favorable, option for pharmacological manipulations of the GABAB receptor. Accordingly, data collected to date suggest that positive allosteric modulators of the GABAB receptor reproduce several “anti-alcohol” effects of baclofen and display a higher therapeutic index (with larger separation – in terms of doses – between “anti-alcohol” effects and sedation).

Alcohol abuse and alcoholism are major medical and social problems worldwide. Unfortunately, pharmacotherapies currently available to physicians do not appear to possess relevant therapeutic efficacy. New medications are needed for the enhancing of abstinence and preventing relapse in alcoholics, as well as for reducing alcohol drinking. Relevant improvements in the pharmacotherapy of alcoholism are conceived to derive from elucidation of the elusive mechanisms of alcohol action in brain. Indeed, only a complete knowledge of how alcohol acts in brain and why drinking is so pleasurable and compelling in some individuals will allow the rational design and development of selective drugs capable of correcting the neurochemical alterations underlying alcohol dependence. The present paper reviews the research advances, at both preclinical and clinical levels, published in the scientific literature as well as the most recent (1998-2001) patent literature.

Background and Objectives Clinical research has proposed that initial sensitivity to ethanol may be negatively correlated with levels of subsequent ethanol intake; consistently, alcohol-preferring P rats were found to be less sensitive to the ataxic and sedative/hypnotic effects of ethanol than -nonpreferring NP rats. The present study investigated the initial sensitivity to the ataxic and sedative/hypnotic effects of ethanol and to the sedative/hypnotic effects of pentobarbital and diazepam in selectively bred Sardinian alcohol-preferring sP and -nonpreferring sNP rats. Methods: In experiment 1, time to lose (onset) and regain (sleep time) the righting reflex after the acute intraperitoneal (ip) administration of 3.0 and 3.5 g/kg ethanol were measured in sP and sNP rats. In experiment 2, sP and sNP rats were required to perform a motor coordination task on a Rota-Rod after the acute intragastric administration of 2.0, 2.5, and 3.0 g/kg ethanol. Experiment 3 assessed onset and sleep time in sP and sNP rats after the acute injection of pentobarbital (40 mg/kg; ip) and diazepam (15 and 20 mg/kg; ip). Results: In experiment 1, sP rats took shorter times to lose the righting reflex and regained this reflex over longer periods of time and at lower blood ethanol levels than sNP rats. In experiment 2, ethanol affected motor coordination to a greater extent in sP than sNP rats. In contrast, results from experiment 3 showed that sP and sNP rats were not differentially sensitive to the sedative/hypnotic effects of pentobarbital and diazepam. Conclusions: The results of experiments 1 and 2 suggest that sP rats possess a genetically determined, greater sensitivity to the motor impairing and sedative/hypnotic effects of ethanol than sNP rats. Although caution should be adopted before hypothesizing any comparison to humans, these results may feature sP rats as an experimental model of those subsets of human alcoholics with initial high sensitivity to ethanol challenges. Finally, the results of experiment 3 suggest a minimal involvement of the benzodiazepine and barbiturate recognition sites in the differential sensitivity to ethanol of sP and sNP rats.

The present paper briefly reviews the most relevant experimental data on the reducing effect of some medicinal herbs on voluntary alcohol intake in animal models of alcoholism. Pueraria lobata, Tabernanthe iboga, Panax ginseng, Salvia miltiorrhiza and Hypericum perforatum proved to be effective in decreasing alcohol consumption. Reduction of alcohol absorption from the gastrointestinal system appears to be a common feature among most of the above plants. These data suggest that medicinal plants may constitute novel and effective pharmacotherapies for alcoholism.

The possible presence of a functional interaction in the constipating effect of opioids and cannabinoids has been assessed. We have measured the ability of the opioid receptor antagonist, naloxone, to antagonize the inhibitory effect of the cannabinoid receptor agonist, WIN 55,212-2, and also, the ability of the cannabinoid CB1-receptor antagonist, SR 141716A, to antagonize the inhibitory effect of morphine, on transit of an orally administered, non-absorbable marker (carmine) in the mouse small intestine. Naloxone failed to alter the reducing effect of WIN 55,212-2 on the propulsive activity; conversely, pretreatment with SR 141716A did not prevent morphine-induced inhibition of marker transit. These results suggest that the constipating effect of opioids and cannabinoids occur through independent and unrelated mechanisms. We assessed also the possible existence of an interaction between CB1 and dopamine D2 receptor systems. The effect of the D2-receptor antagonist, S(-)-sulpiride, on the inhibiting effect of WIN 55,212-2 and of SR 141716A on the inhibiting effect of the D2 agonist, bromocriptine, on intestinal propulsion were assessed. Combination of 50 mg kg−1S(-)-sulpiride and 0.5 mg kg−1 WIN 55,212-2, but not higher doses, resulted in the blockade of WIN 55,212-2 effect; similarly, combination of 0.1 mg kg−1 SR 141716A abolished bromocriptine-induced decrease in intestinal motility. These results suggest the existence of a functional interaction between the CB1 and D2 receptors in mouse intestinal motility.

The present paper reviews the drug discrimination studies, both from the literature and from this laboratory, conducted to investigate the pharmacological profile of the discriminative stimulus effects of gamma-hydroxybutyric acid. Collectively, the results of these studies suggest that: (1) the discriminative stimulus effects of gamma-hydroxybutyric acid are composed of different cues, each one being the effect of gamma-hydroxybutyric acid on a specific receptor system; (2) the proportion of each component cue varies as the training dose of gamma-hydroxybutyric acid is increased; (3) the gamma-aminobutyric acid B-mediated cue is a major ingredient of the mixed stimulus of gamma-hydroxybutyric acid, but it is more prominent at high training doses than at low training doses of gamma-hydroxybutyric acid; and (4) positive modulation of the gamma-aminobutyric acid A receptor is a relevant part of the discriminative stimulus effects of low gamma-hydroxybutyric acid doses. Finally, data indicating symmetrical generalization between the discriminative stimulus effects of a specific range of doses of gamma-hydroxybutyric acid and those of ethanol are discussed in regard to their further support of the hypothesis that gamma-hydroxybutyric acid may exert its antialcohol effects through a substitution mechanism.

Background: The similarities between the pharmacological effects of the γ-aminobutyric acid receptor agonist, baclofen, and the alcohol-substituting agent, γ-hydroxybutyric acid, led us to investigate whether baclofen was capable of reducing (a) ethanol withdrawal syndrome in ethanol-dependent rats and (b) voluntary ethanol intake in ethanol-preferring rats. Methods: In experiment 1, Wistar rats were rendered physically dependent on ethanol by the repeated administration of intoxicating doses of ethanol for 6 consecutive days. Baclofen was acutely administered intraperitoneally at doses of 10, 20, and 40 mg/kg. In experiment 2, baclofen (0, 2.5, 5, and 10 mg/kg, intraperitoneally) was administered once a day for 14 consecutive days to ethanol-preferring sP rats that had continuous access to ethanol (10%, v/v) and water under the two-bottle free choice regimen. Results: In experiment 1, baclofen dose-dependently decreased the intensity of ethanol withdrawal signs; furthermore, 20 mg/kg of baclofen protected from audiogenic seizures in ethanol-withdrawn rats. In experiment 2, baclofen selectively and dose-dependently reduced voluntary ethanol intake; a compensatory increase in water intake left total fluid intake virtually unchanged. Conclusions: These results are in close agreement with those of a preliminary clinical study and suggest that baclofen may constitute a novel therapeutic agent for alcoholism.

studies [8–10]. The first study found that 32 IU of oxytocin nasal spray induced better results in patients with chronic migraine if they had not taken NSAIDs [8]. However, this study failed to report the number of patients and statistical evaluation. The second study found that 40 IU of oxytocin (twice a day, for 13 weeks) reduced abdominal discomfort but not constipation in 59 women with refractory constipation [9]. However, this study did not report whether NSAIDs were used or not [1, 9]. The third study found that oxytocin dose dependently reduced the severity of headache in 112 patients not taking analgesic medications [10]. However, the doses of oxytocin were not specified. It is reported that patients received six puffs of a solution containing different concentrations of oxytocin (100, 200 or 400 ng) without specifying whether these concentrations were referred to 1 ml, to 1 puff, or to 6 puffs. Considering that usually 1 puff consists of 0.1 ml of solution, and 1 IU corresponds to 2 μg of oxytocin [11], we calculated the maximum dose of oxytocin expressed in IU. If the highest dose (400 ng) was referred to 1 ml, each patient received 0.12 IU (400 ng/ml; each patient received 0.6 ml; 0.6 ml contains 240 ng, corresponding to 0.12 IU); if the dose was referred to 1 puff, each patient received 1.2 IU (400 ng/ puff; 400 ng × 6 = 2,400 ng corresponding to 1.2 IU); if it referred to the total of 6 puffs, each patient received 0.2 IU (400 ng/6 puffs corresponding to 0.2 IU). Accordingly, the maximum dose administered (1.2 IU) would be much lower than those usually administered. For instance, 27 and 33 times lower than that used in the first (32 IU) and in the second study (40 IU), respectively [8, 9]. The limits of these studies did not allow any conclusions to be drawn on the possible influence of NSAIDs on the effects induced by oxytocin. It has been observed that NSAID administration reduces the secretion of endogenous oxytocin [12], although this effect should not influence response We read with interest the Commentary of Drs. Kwong and Chan on the lack of analgesic effects induced by the administration of oxytocin nasal spray to fibromyalgic patients [1–3]. We agree with them that these negative results are very disappointing, particularly as the inverse relationship between plasma oxytocin levels and the severity of pain found by other studies persuaded us to conduct our study [4]. We also agree with them on the possibility that the severity of pain may change throughout the menstrual cycle of fertile women. Indeed, in fibromyalgic patients, the severity of pain is higher in the luteal than in the follicular phase [5], and, in healthy fertile women, plasma oxytocin levels are lower during the luteal than the follicular phase [6]. The expression of brain oxytocin receptors is modulated by estrogen and progesterone [7]. However, in our study, patients included seven postmenopausal and seven premenopausal women, most of the latter with irregular cycles (n = 5). This sample was not adequate to investigate possible swing of fibromyalgic symptoms throughout the menstrual cycle. Finally, we read with great interest the hypothesis that the lack of efficacy of oxytocin may be due to the use of nonsteroidal anti-inflammatory drugs (NSAIDs) [1]. This hypothesis was based on the results of three clinical

Experiment 1 in the present study investigated the time course and dose range of gamma-hydroxybutyric acid (GHB) to reduce voluntary ethanol intake in selectively bred Sardinian ethanol-preferring (sP) rats. Ethanol (10%, v/v) and tap water were offered under the two-bottle free choice regimen with unlimited access. GHB (200, 300, and 400 mg/kg, i.p.) was administered 15 20 min prior to the start of the dark phase of the light-dark cycle. Ethanol and water intakes were recorded at different time intervals during the dark phase. GHB significantly reduced ethanol intake at doses of 300 and 400 mg/kg; statistical significance occurred only at the 15-min and 30-min observation times. The GHB dose of 300 mg/kg was devoid of any sedative effect, as demonstrated in Experiment 2 by the lack of any impairment of spontaneous locomotor activity. Finally, this dose of GHB was also found to exert a robust anxiolytic effect in sP rats tested on the elevated plus maze (Experiment 3). Collectively, the results of the present study demonstrate that a non-sedative and anxiolytic dose of GHB effectively reduced voluntary ethanol intake in sP rats. The rapid onset of the reducing effect of GHB on ethanol intake, as well as its anxiolytic effect, are discussed in terms of adding further support to the hypothesis that GHB may control alcohol craving and consumption in humans by substituting for ethanol's reinforcing effects.

The effect of the cannabinoid CB1 receptor antagonist, SR 141716, on food intake and body weight was assessed in adult, non-obese Wistar rats. The daily administration of SR 141716 (2.5 and 10 mg/kg; i.p.) reduced dose-dependently both food intake and body weight. Tolerance to the anorectic effect developed within 5 days; in contrast, body weight in SR 141716-treated rats remained markedly below that of vehicle-treated rats throughout the entire treatment period (14 days). The results suggest that brain cannabinoid receptors are involved in the regulation of appetite and body weight.

The present study was designed to further investigate the pharmacological profile of the discriminative stimulus effects of gamma-hydroxybutyric acid (GHB). Drugs acting at the gamma-aminobutyric acid (GABA)B receptor (baclofen and CGP 35348), GABA(A)/benzodiazepine receptor complex (diazepam), N-methyl-D-aspartate (NMDA) receptor complex (dizocilpine), and cannabinoid receptor (WIN 55,212-2) were tested for substitution or blockade of the GHB interoceptive cue in rats trained to discriminate either 300 or 700 mg/kg of GHB i.g. from water in a T-maze, food-reinforced drug discrimination paradigm. Baclofen completely substituted for both training doses of GHB; however, its potency in substituting for GHB increased as the training dose of GHB was increased. CGP 35348 partially and completely blocked the cue elicited by 300 and 700 mg/kg of GHB, respectively. In contrast, diazepam partially substituted for 300 mg/kg of GHB, while failing to produce a GHB-appropriate response in the rat group trained to the higher GHB dose. Neither dizocilpine nor WIN 55,212-2 substituted for GHB. Collectively, these data suggest that: a) GHB produces a compound stimulus; and b) GABA(B)- and GABA(A)-mediated cues are prominent components of the mixed stimulus of GHB. However, the quality (i.e., the proportion of the component cues) of the stimulus varies as the training dose of GHB is increased; indeed, the contribution of the GABA(A)- and GABA(B)-mediated cues were smaller and greater, respectively, at 700 and 300 mg/kg of GHB training doses.

The present study was aimed at determining whether the concurrent availability of highly palatable fluids (i.e., a chocolate-flavored drink and a sucrose solution) would alter voluntary ethanol drinking in selectively bred, alcohol-preferring sP and -nonpreferring sNP rats. Ethanol intake occurred under the three-bottle, free choice regimen between 10% ( v v ) ethanol solution, tap water, and the palatable fluids for 24 h per day. When rats were given ethanol and water, but no alternative fluids, mean ethanol intake in sP rats ranged between 6 and 7 g/kg per day and mean preference ratio was steadily higher than 80%, whereas mean ethanol intake and preference ratio in sNP rats were constantly lower than 0.3 g/kg and 5%, respectively. In the presence of either the chocolate-flavored drink or sucrose solution, both prepared as isocaloric to the ethanol solution, absolute ethanol intake in sP rats declined by 60–70%; similarly, the preference ratio was reduced by 80–90%. Ethanol intake in sNP rats was unaffected by the simultaneous presentation of either palatable fluids. The results of the present study closely replicate those previously reported in genetically selected, ethanol-preferring HAD rats; however, they differ from those of ethanol-preferring P rats, which were reported to maintain high levels of ethanol intake and preference in the presence of highly palatable fluids. These results are discussed in terms of a) an alternative reinforcement partially substituting for the reinforcing properties of ethanol in sP rats, resulting in a less urgent need of ethanol, and b) genetic animal models of alcoholism diverging in some neurochemical and behavioral traits (e.g., response to the presentation of palatable fluids), which might parallel the different types of alcoholism observed in humans.

Aims: Alcopops are ready-mixed drinks containing approximately the same amount of alcohol as beer, usually sweet, and flavoured, particularly appealing to young people. The present study was aimed to investigate whether young adolescents aged 12-14 years, corresponding to the average age of the first drink, are capable of identifying the presence of alcohol in these beverages. Methods: Administration of a questionnaire comprising 8 questions investigating knowledge and consumption of different alcoholic and non-alcoholic beverages to a sample of 13-year old Italian students. Results: More than 20% of a sample of 224 students reported that they were unaware of the alcoholic content of alcopops at the age of the first drink. The number of students unable to distinguish alcopops from non-alcoholic beverages was significantly higher than students who were not able to distinguish beer from alcohol-free beverages. Conclusions: At the age of the first drink, the identification of alcopops as alcoholic beverages is more difficult than that of other beverages containing the same amount of alcohol. Information aimed at increasing the ability of adolescents to distinguish between alcoholic and non-alcoholic beverages should be provided to young adolescent students before they start drinking.

Background: It has been reported that baclofen, a drug used in the treatment of spasticity, reduces the severity of withdrawal symptoms and substance use disorders (SUDs) for some psychoactive drugs. Aims and Methods: To evaluate the effectiveness and safety of baclofen in the treatment of withdrawal syndrome and/or SUDs, providing (1) an outline of its pharmacological features; (2) a summary of studies that have suggested its possible effectiveness in the treatment of SUDs, and (3) a review of randomized, controlled trials (RCTs) on baclofen and SUDs. Results: Baclofen tolerability is generally considered to be good. Eleven RCTs investigated its effectiveness in the treatment of SUDs. Of these, 5 RCTs found that baclofen is effective, 5 RCTs found that it is ineffective and the results of 1 RCT were not appreciable because it did not achieve the preplanned level of participation. Conclusions: The number of RCTs on baclofen and SUDs is still low, and their results are divergent. Further RCTs should be undertaken, particularly with higher doses of baclofen. Its administration may be suggested in patients who fail to respond to other approved drugs or who are affected by liver disease that prevents their administration, or in patients affected by SUDs for which no approved drugs are available. Treatment should be conducted under strict medical supervision.

The present study was designed to assess the temporal pattern of ethanol intake over a 24 h period in selectively bred, Sardinian alcohol-preferring (sP) rats. Ethanol intake occurred under the two-bottle, free choice regimen. sP rats consumed ethanol in three distinct peaks, rather regularly distributed over the 12 h dark phase of the light-dark cycle and positively correlated with food intake episodes. The temporal distribution of ethanol intake and estimated blood alcohol levels are consistent with the hypothesis that sP rats voluntarily drink ethanol for its pharmacological effects.

The present study describes the induction of γ-hydroxybutyric acid (GHB) preference over water in rats. GHB solution (1% w / v in water) was initially offered as the sole fluid available for 14 consecutive days. Subsequently, rats were given a free choice of GHB solution and tap water for 20 consecutive weeks. Under the free-choice regimen, all rats showed periods of preference for GHB solution over water and periods of voluntary abstinence from GHB. On GHB-preference days, GHB was ingested at pharmacologically relevant doses. GHB intake occurred in 2–3 discrete episodes during the nocturnal phase. The development of an animal model of GHB self-administration may constitute a useful tool in the investigation of the neurobiological substrates of GHB-reinforcing properties.

The present study was designed to assess the anxiety profile of the selectively bred alcohol-preferring sP and alcohol-nonpreferring sNP rats. Rats were offered either water (ethanol-naive rats) or a free choice of 10% (v/v) ethanol and water (ethanol-experienced rats) for 14 consecutive days prior to the test. Spontaneous exploration of an elevated plus maze was used as a behavioral measure of anxiety. Ethanol-naive sP rats spent less time in and made fewer entries into the open arms of the maze than ethanol-naive sNP rats. These results suggest a higher innate degree of anxiety in sP than in sNP rats. Moreover, time spent in and number of entries into the open arms of the maze were higher in ethanol-experienced than in ethanol-naive sP rats. This finding suggests that ethanol consumed voluntarily produces anxiolytic effects in sP rats. The results of the present study are discussed in terms of (a) anxiety as a genetic trait related to ethanol-preference in sP rats and (b) self-medication of anxiety as a possible factor promoting voluntary ethanol consumption in sP rats.

Gamma-hydroxybutyric acid (GHB) has been shown to reduce ethanol consumption and suppress ethanol withdrawal syndrome both in laboratory animals and humans. The present study was designed to assess the similarity between the discriminative stimulus effects, or subjective feelings, of GHB and ethanol using a T-maze, food-reinforced drug discrimination procedure. Three groups of rats were trained to discriminate ethanol (1.0 or 2.0 g/kg; p.o.) or GHB (300 mg/kg; p.o.) from water. In the 1.0 g/kg ethanol-trained rats, substitution for ethanol was an inverted U-shape function of GHB dose, with only 300 mg/kg GHB resulting in complete substitution for ethanol. No dose of GHB elicited selection of ethanol-appropriate arm higher than 10% in the 2.0 g/kg ethanol-trained group. In the 300 mg/kg GHB-trained rats, complete substitution for GHB occurred only at the dose of 1.0 g/kg ethanol. Doses of ethanol lower or higher than 1.0 g/kg did not substitute for GHB. The results of the present study indicate that symmetrical generalization between ethanol and GHB occurred within narrow dose ranges. They are discussed in terms of common neurotransmitter systems involved in the mediation of GHB and ethanol effects.

The present paper summarizes experimental and clinical data suggesting the therapeutic potential of the prototypic GABAB receptor agonist, baclofen, for the treatment of alcohol-use disorders (AUDs). Numerous studies have reported baclofen-induced suppression of alcohol drinking, relapse-like drinking, and alcohol reinforcing, rewarding, stimulating, and motivational properties in rats and mice. The majority of clinical surveys conducted to date have demonstrated the capacity of baclofen to suppress alcohol consumption, craving for alcohol, and alcohol withdrawal symptomatology in alcohol-dependent patients. More recently, the discovery of a positive allosteric modulatory binding site, together with the synthesis of in vivo effective ligands, provided a new tool for pharmacological manipulations of the GABAB receptor. Accumulating lines of preclinical evidence suggest that positive allosteric modulators of the GABAB receptor (GABAB PAMs), such as GS39783, display a high therapeutic index and retain baclofen's capacity to suppress alcohol consumption and alcohol reinforcing and motivational properties. The present paper also summarizes the most relevant patents on GABAB receptor agonists and GABAB PAMs as possible pharmacotherapies for AUDs.

The effect of the dihydropyridine Ca2+ channel antagonist, isradipine, on ethanol discrimination was assessed in rats trained to discriminate 1.5 g/kg ethanol from water in a T-maze, food-reinforced drug discrimination procedure. Pretreatment with isradipine (0, 1.0, 3.0 and 5.0 mg/kg i.p.) resulted in a dose-dependent blockade of ethanol discrimination. The results of the present study suggest that L-type Ca2+ channels are involved in the mediation of ethanol discriminative stimulus effects.

A possible acute, analgesic effect of oxytocin was investigated at the beginning of the study. After baseline evaluation, patients self-administered oxytocin (20-IU) or placebo and waited for 1 h, when central oxytocin levels achieve the highest values [4–6]. Then, the severity of actual pain was investigated, but no difference was found (placebo 43.3 ± 10.6; oxytocin 47.2 ± 16.2, p = 0.15, t test). The acute effects of 40-IU was not examined as patients started with this dose after 1 week of a 20-IU treatment, and this evaluation would not be a reliable measure of 40-IU acute effects. Under our experimental conditions, chronic treatments with 20-IU or 40-IU did not reduce the severity of pain. We concluded that higher doses or long periods of treatment might unravel an analgesic effect of oxytocin. Recent studies found that 24-IU of oxytocin (1) induced stronger effects than 48-IU in cortisol response to intense exercise [7] and (2) was effective in reducing obesity if administered 4 times daily for 8 weeks [8]. Accordingly, the ideal schedule seems to be constituted by more frequent daily administrations of lower doses, and for longer periods of time than those used in our studies (e.g., 24-IU, 4 times daily for at least 8 weeks rather than 40-IU twice daily for 3 weeks). Despite the large body of preclinical evidence suggesting an analgesic effect of oxytocin, the number of clinical studies is scarce. A recent review [9] reported that only five studies investigated this effect: among these, three studies found positive effects [10–12], one promising results [13], and one inconclusive results [14]. Recently, two additional clinical studies found opposite results [2, 15]. The difference between results may be due, at least in part, to the different patient samples (fibromyalgic patients vs. healthy adults) and methodological procedures (chronic vs. acute treatment; chronic unresponsive vs. acute cold pressor pain). We read with interest the letter of Drs. Rash and Campbell [1] and are grateful to them for the opportunity to provide additional information to our short communication [2]. Regarding the procedure of the administration, the recommendations suggested by Guastella and colleagues were adopted [3]. During the first week, the dose was equal to 5 puffs (20-IU) twice a day, then, to 10 puffs (40-IU) twice a day. The composition of the oxytocin and placebo nasal sprays was identical, except for the hormone. It is difficult to determine what influence the expectation of effects had on our results, as no data were collected on expectations. However, the lack of differences between the groups suggests that oxytocin did not enhance placebo analgesia in our experimental conditions. Our study was aimed at investigating the possible effectiveness of chronic treatment in reducing the severity of pain. Accordingly, medications were self-administered by participants, twice daily, with a 12-h interval, for 3 weeks. patients registered the severity of pain at the end of the day, regardless of the time of the administration. At each weekly visit, the experimenter registered the severity of pain, regardless of the time of administration.

γ-Hydroxybutyric acid (GHB) is a naturally occurring constituent of the mammalian brain, where it likely functions as neurotransmitter or neuromodulator. When exogenously administered, GHB exerts a variety of psychopharmacological effects, including euphoria, anxiolysis, sedation, and anesthesia. Most of these effects appear to be mediated by activation of the GABAB receptor, although a GHB-specific binding site has also been described. Applications of GHB in the treatment of narcolepsy and alcoholism have been proposed. Recreational use of GHB, often leading to cases of intoxication, dependence and withdrawal, has dramatically spread over the past 20 years.

The present study examined the involvement of GABA(A) and GABA(B) receptors in the discriminative stimulus effects of gamma-hydroxybutyric acid (GHB). Rats were trained to discriminate either 300 or 700 mg/kg GHB IG from water using a T-maze, food-reinforced drug-discrimination procedure. The direct GABA(B) agonist, baclofen, substituted completely for both training doses of GHB; its potency to substitute for GHB increased moderately as the training dose of GHB was increased. The positive GABA(A) modulator, diazepam, substituted partially for 300 mg/kg GHB, but failed to elicit GHB-appropriate responding in rats trained with the higher GHB dose. Finally, the GABA(B) antagonist, CGP 35348, completely blocked the discriminative stimulus effects of the high training dose of GHB, but only partially antagonized the effects of the low training dose. These results suggest that (a) GHB produces a compound stimulus, and (b) both GABA(B)- and GABA(A)-mediated cues are prominent components of this compound stimulus; the contribution of each component, however, appears to vary as the training dose of GHB is increased.

The present study demonstrates that the gamma-hydroxybutyric acid receptor antagonist, NCS-382, markedly reduces blood ethanol levels (BELs) in rats when ethanol is administered via the intragastric route, whereas it is completely ineffective when ethanol is injected IP. The reducing effect of NCS-382 on BELs is likely due to a lessened absorption of ethanol from the gastrointestinal tract.

Aims: To evaluate the number of subjects with possible alcohol use disorders (SPAUD) among primary care patients in Cagliari, Sardinia, Italy, by means of the self-administration of Alcohol use disorder identification test (AUDIT) and CAGE questionnaires. Methods: 939 patients waiting in 10 surgeries of primary care physicians were asked to take part in the study. A sample of 309 women and 197 men (total 506), aged between 18 and 65 years, agreed to participate and completed both questionnaires. SPAUD were defined as those achieving cut-off scores of 5 for AUDIT and/or 1 for CAGE. Results: Seventy-nine (15.61%) patients were SPAUD, achieving a positive score in at least one questionnaire. Fifty-six (11.07%) and forty-six (9.09%) patients yielded positive results with AUDIT and CAGE, respectively. Twenty-three (4.55%) patients were positive at both AUDIT and CAGE. Significantly higher proportions of men than women were recorded among SPAUD.Conclusions:The results of the present survey indicate a high number of SPAUD in a sample of primary care settings in Cagliari, closely similar to the occurrence of alcohol use disorders estimated in several other community-based primary care clinics in Western Countries.

This chapter describes the clincial experience related to the use of Baclofen as a pharmacological treatment of alcohol withdrawal syndrome.

Purpose Benzodiazepines are the drugs of choice in the treatment of alcohol withdrawal syndrome (AWS). Recent data have shown that baclofen may reduce AWS symptoms. At present, no comparative studies between baclofen and any benzodiazepine used in AWS treatment are available. Accordingly, the present study was designed to compare efficacy, tolerability and safety of baclofen versus diazepam in the treatment of AWS. Subjects and methods Thirty-seven patients with AWS were enrolled in the study and randomly divided into 2 groups. Baclofen (30 mg/day for 10 consecutive days) was orally administered to 18 patients (15 males, 3 females; median age: 46.5 years). Diazepam (0.5-0.75 mg/kg/day for 6 consecutive days, tapering the dose by 25% daily from day 7 to day 10) was orally administered to 19 patients (17 men, 2 women; median age: 42.0 years). The Clinical Institute Withdrawal Assessment (CIWA-Ar) was used to evaluate physical symptoms of AWS. Results Both baclofen and diazepam significantly decreased CIWA-Ar score, without significant differences between the 2 treatments. When CIWA-Ar subscales for sweating, tremors, anxiety and agitation were evaluated singly, treatment with baclofen and diazepam resulted in a significant decrease in sweating, tremors and anxiety score, without significant differences between the 2 drug treatments. Both treatments decreased the agitation score, although diazepam was slightly more rapid than baclofen. Conclusion The efficacy of baclofen in treatment of uncomplicated AWS is comparable to that of the "gold standard" diazepam. These results suggest that baclofen may be considered as a new drug for treatment of uncomplicated AWS.

The effect of acutely administered gamma-hydroxybutyric acid (GHB) and GHB receptor antagonist, NCS-382, on the propulsive activity in the mouse small intestine was assessed by measuring the transit of an orally administered, non absorbable marker. Both GHB (0, 25, 50, 100, 200 and 300 mg/kg; i.p.) and NCS-382 (0, 25, 50 and 75 mg/kg; i.p.) induced a dose-dependent inhibition (up to 50–60%) of the marker transit. Pretreatment with the GABA B receptor antagonist, SCH 50911 (100 mg/kg; i.p.), resulted in the blockade of the inhibiting effect of both GHB and NCS-382. These results suggest that the constipating effect of GHB and NCS-382 are secondary to stimulation of the GABA B receptor.

Alcohol deprivation effect (ADE), defined as a temporary increase in voluntary alcohol intake following a period of alcohol abstinence, was evaluated in selectively bred Sardinian alcohol-preferring (sP) rats. Alcohol was initially offered in free choice with water for 35 consecutive days (predeprivation phase). Subsequently, one group of rats was deprived of alcohol for 1, 3, 7, 15, 30, 90 or 180 consecutive days, while the second group had continuous access to alcohol (deprivation phase). Once alcohol was re-presented, alcohol intake in alcohol-deprived rats was recorded 1 and 24 h after alcohol re-presentation and compared to that monitored in alcohol-nondeprived rats over the same time periods (postdeprivation phase). Alcohol deprivation for 3 to 30 days resulted in a significant increase in voluntary alcohol intake only in the first hour of re-access. These results demonstrate the development of ADE in sP rats. However, the rapid return of alcohol intake to control levels is discussed as evidence in favor of a set-point mechanism capable of regulating alcohol-drinking behavior in sP rats.

Treatment with gamma-hydroxybutyric acid has been reported to effectively decrease alcohol craving and consumption as well as alcohol withdrawal symptoms in alcoholics. We describe the results of animal studies demonstrating the ability of gamma-hydroxybutyric acid to reduce (1) the severity of ethanol withdrawal signs in rats rendered physically dependent on ethanol and (2) voluntary ethanol intake in selectively bred Sardinian alcohol-preferring rats. Furthermore, we review experimental data suggesting that gamma-hydroxybutyric acid and ethanol have several pharmacological effects in common. Relevant similarities are: (1) stimulation of firing rate of dopaminergic neurons and dopamine release in specific rat brain areas; (2) development of cross-tolerance to the motor-impairing effects after repeated administration in rats; 3) abuse potential, as indicated by self-administration of pharmacologically relevant doses of gamma-hydroxybutyric acid in rats and mice; (4) induction of anxiolytic effects in rats; and (5) induction of similar discriminative stimulus effects, as evidenced by symmetrical generalization in a drug discrimination study in rats. These lines of evidence are discussed in relation to gamma-hydroxybutyric acid exerting its antialcohol effects by a substitution mechanism.

Background: It has been proposed that ethanol intake and consumption of sweet tasting solutions are positively correlated in rodents. Experiment 1 of the present study investigated whether selectively bred ethanol-preferring (sP) and -nonpreferring (sNP) rats differed, consistently with the above hypothesis, as to saccharin intake and preference. Experiment 2 evaluated whether saccharin addition to the ethanol solution, likely resulting in a highly palatable fluid, would result in an increase in voluntary ethanol intake in sP rats. Methods: The saccharin solution was offered, in free choice with water, at a fixed concentration of 1 giliter for 6 consecutive days in Experiment 1A or at ascending concentrations (0.002 to 16.4 g/liter, doubling the concentration every day) in Experiment 1B. In Experiment 2, 1 g/liter, doubling the concentration every day) in Experiment 1B. In Experiment 2, 1 g/liter saccharin was added to the standard 10% ethanol solution and offered to sP rats in free choice with water for 7 consecutive days. Results: In both Experiments 1A and 1B, sP and sNP rats showed avidity for the saccharin solution with marginal line difference in saccharin intake and preference. In Experiment 2, daily ethanol intake remained stable at baseline levels (6–7 g/kg), irrespective of the saccharin addition to the ethanol solution. Conclusions: The results of Experiments 1A and 1B suggest that saccharin drinking behavior in sNP rats deviates from the hypothesis that saccharin and ethanol intakes may co-vary; thus, at least in sNP rats, saccharin and ethanol intakes do not appear to be influenced by the same genetic factors. The results of Experiment 2 provide further support to the existence of a central set-point mechanism that regulates daily ethanol intake in sP rats, likely based on the pharmacological effects of ethanol.

Alcohol administration (1 g/kg, i.p.) increased the levels of the neurosteroids 3alpha-hydroxy-5alpha-pregnan-20-one (allopregnanolone) and 3alpha,21-dihydroxy-5alpha-pregnan-20-one (allotetrahydrodeoxycorticosterone, THDOC) in the cerebral cortex and hippocampus both in alcohol-naive Sardinian alcohol-preferring (sP) and -non-preferring (sNP) rats (two rat lines selectively bred for alcohol preference and non-preference, respectively). However, the increase reached several fold higher levels in sP than in sNP rats (6-24 vs. 2-11 fold the basal levels, respectively). Since the two neurosteroids are the most potent endogenous positive modulators of GABA(A) receptors and elicit anxiolytic and rewarding effects, while voluntary alcohol consumption produces anxiolytic and rewarding effects in sP but not in sNP rats, the results suggest that the neurosteroids may play a role in the anxiolytic and rewarding effects of alcohol in sP rats.

Experiment 1 of the present study investigated the ability of a standardized extract of Salvia miltiorrhiza in reducing voluntary ethanol intake in ethanol-preferring rats of the sP line. Ethanol intake occurred under the two-bottle free-choice regimen between 10% (v/v) ethanol and water in daily 4-h scheduled access periods; water was present 24 h/day. Intragastric administration of 200 mg/kg Salvia miltiorrhiza extract resulted in approximately 40% reduction in ethanol intake and preference throughout the 4-day treatment. This effect of Salvia miltiorrhiza extract was likely due to its ability of altering ethanol absorption from the gastrointestinal tract. Indeed, Experiments 2 and 3 of this study demonstrated that 200 mg/kg Salvia miltiorrhiza extract reduced blood ethanol levels (BELs) up to 60% in comparison to control rats, when ethanol was given IG, whereas it failed to modify BELs when ethanol was injected IP. The reducing effect of Salvia miltiorrhiza extract on ethanol absorption may have therefore resulted in an attenuated perception of the psychoactive effects of ethanol sought by ethanol-drinking rats. Consistently, the results of Experiment 4 of the present study demonstrated that a combination of 200 mg/kg Salvia miltiorrhiza extract IG and 1 or 2 g/kg ethanol IG resulted in a partial blockade of the discriminative stimulus effects of ethanol in sP rats trained to discriminate these doses of ethanol from water in a drug discrimination procedure. Collectively, the results are discussed as being suggestive that drugs curbing ethanol absorption from the gastrointestinal tract may constitute a novel strategy for controlling excessive alcohol consumption in human alcoholics.

Stimulation of motor activity induced by ethanol has been proposed to reflect the positive reinforcing properties of the drug. The present study was designed to assess whether voluntary ethanol intake would stimulate locomotor activity in Sardinian alcohol-preferring (sP) rats, selectively bred for high ethanol preference and consumption. Rats were habituated to a) consume either water alone (water-consuming rats) or ethanol (10%, v/v) as free choice together with water (ethanol-consuming rats) according to a 15-min limited access protocol for 10 consecutive days prior to the test, and b) explore an open field for 10 min immediately after the drinking session in a trial on 3 consecutive days before the test. On the test day, voluntary ethanol consumption in ethanol-consuming rats averaged 1.2 g/kg. Values for activity measures (time spent moving, number of square crossings and number of rearings) were significantly higher in ethanol- than in water-consuming rats at both 5- and 10-min intervals. These results suggest that the euphorigenic effects of ethanol, supposedly represented by the stimulation of locomotor activity, are part of the reinforcing properties of ethanol in sP rats.

COLOMBO, G., R. AGABIO, G. DIAZ, M. FA, C. LOBINA, R. REALI AND G. L. GESSA. γ-Hydroxybutyric acid intake in ethanol-preferring sP and -nonpreferring sNP rats. Physiol Behav 64(2) 197–202, 1998. γ-hydroxybutyric acid (GHB) and ethanol share several pharmacological similarities, suggesting that GHB may exert ethanol-like effects in the central nervous system. The present study was designed to test whether selectively bred ethanol-preferring rats would, unlike ethanol-nonpreferring ones, self-administer GHB, consistent with their higher preference for ethanol. Male ethanol-naive Sardinian alcohol-preferring (sP) and Sardinian alcohol-nonpreferring (sNP) rats were used. In Experiment 1, GHB solution (1% (w/v) in water) was initially offered as the sole fluid available for 14 consecutive days and then presented under the two-bottle, free-choice regimen, one bottle containing water and the other the GHB solution, for an additional 14 consecutive days. During the free-choice phase, high preference for GHB and intake of pharmacologically relevant daily doses of GHB developed in both rat lines, presumably because the 14-day no-choice period would unmask the reinforcing properties of GHB and lead to acquisition of GHB preference also in the supposedly less susceptible sNP rats. In Experiment 2, the forced GHB drinking phase was reduced to 3 days. Under the subsequent free-choice regimen, daily GHB preference and intake were initially low in both sP and sNP rats; however, after approximately 10 days, GHB preference and intake in sP rats rose progressively and then stabilized to significantly higher levels than in sNP rats throughout the entire free-choice phase. It is likely that episodic binges of GHB intake occurring during the first 10 days resulted in experiencing the reinforcing properties of GHB by sP but not sNP rats. The results of the present study suggest that a) sP rats are genetically more sensitive to the reinforcing effects of both ethanol and GHB than sNP rats; and b) disclosure of the higher sensitivity of sP rats to the reinforcing effects of GHB is a function of the length of the induction procedure. The results are also discussed in terms of differences in GHB receptors contributing to the predisposition to ethanol preference and avoidance, respectively.

The effect of cannabinoid receptor activation and blockade on the propulsive activity in the mouse small intestine was assessed in the present study by measuring the transit of an orally administered, non-absorbable marker. The cannabinoid receptor agonist WIN 55,212-2 ( R (+)-[2,3-dihydro-5-methyl-3[(morpholinyl)methyl]pyrrolo[1,2,3-de-1,4benzoxazin-yl]-(1-naphthalenyl)methanone mesylate) inhibited, while the selective cannabinoid CB 1 receptor antagonist SR 141716A ( N -piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide) stimulated the marker transit. Furthermore, a per se non-effective dose of SR 141716A reversed WIN 55,212-2-induced reduction of the transit. The results of the present study suggest a role for cannabinoid CB 1 receptors in the control of propulsive activity in the mouse small intestine.

The present study was designed to evaluate ethanol drinking behaviour in Sardinian alcohol-preferring (sP) and Sardinian alcohol-non-preferring (sNP) rats in the presence of different ethanol concentrations. Ethanol intake was tested under the two-bottle, free-choice regimen and continuous access schedule. Ethanol-naive sP and sNP rats were initially given ethanol solution at the standard, constant concentration of 10% (v/v) for 8 consecutive days (Phase 1). As expected, daily ethanol intake in sP rats rose from 4 to approximately 6 g/kg; in contrast sNP rats consumed10 g/kg/day ethanol. Subsequently, an ascending series of ethanol concentrations, ranging from 3 to 60% (v/v), was presented to sP and sNP rats over a 28-day period (Phase 2). At concentrations varying from 7 to 30%, sP rats consumed constant amounts of absolute ethanol per kg of body weight (approximately 6.0 g/kg/day). Daily ethanol intake in sNP rats remained constantly lower than 1.0 g/kg, irrespective of the ethanol concentration. Data from Phase 2 demonstrate the ability of sP rats to precisely adjust daily ethanol intake and support the hypothesis that voluntary ethanol drinking in sP rats is sustained by specific pharmacological effects of ethanol.

( Received 28 August 2004; first review notified 12 September 2004; in revised form 28 September 2004; accepted 7 October 2004 ) Thiamine (vitamin B1) is a water-soluble vitamin that is involved in the metabolism of glucose and lipids as well as in the production of glucose-derived neurotransmitters (see Cook et al ., 1998). Its deficiency leads to a variety of neurological and cardiovascular symptoms and signs. Early symptoms may include fatigue, weakness and emotional disturbance, whereas prolonged gradual deficiency may lead to a form of polyneuritis (known as dry beriberi), cardiac failure or peripheral oedema (wet beriberi) (Thomson, 2000). Severe thiamine deficiency (TD) may result in the development of Wernicke's encephalopathy (WE). The classical signs of WE are ocular motility disorders (nystagmus, ophthalmoplegia), ataxia and mental changes (confusion, drowsiness, obtundation, clouding of consciousness, pre-coma and coma), although minor episodes of 'subclinical' encephalopathies are frequent (Reuler et al ., 1985). An appropriate treatment may correct most of these abnormalities; in contrast, the lack of a diagnosis of WE may result in serious consequences (Reuler et al ., 1985 …

The present study was designed to assess the ability of the newly synthetized, selective gamma-hydroxybutyric acid (GHB) receptor antagonist, NCS-382, in blocking the discriminative stimulus effects of GHB in a T-maze, food-reinforced drug discrimination procedure. Two groups of rats were trained to run the left arm of the maze 30 min after the i.g. administration of either 300 or 700 mg/kg GHB and the right arm after water. Once discrimination was acquired, combination of different doses of NCS-382 (0, 12.5, 25.0 and 50.0 mg/kg, IP) and GHB training doses were tested for blockade of GHB discrimination. NCS-382 dose-dependently blocked GHB-appropriate responding in both the 300 and 700 mg/kg GHB rat groups. The results of the present study indicate that the discriminative stimulus properties of GHB are mediated via stimulation of GHB receptors.

In the present study, the development of tolerance to the motor impairing effects of γ-hydroxybutyric acid (GHBA) and ethanol was compared (Experiment 1). Rats were required to perform a motor coordination task daily shortly after ethanol (3.5 g/kg) and GHBA (1.0 g/kg) administration for 9 consecutive days. Tolerance to the motor impairing effects of ethanol and GHBA developed to a similar extent but with different patterns. On the tenth day, the presence of cross-tolerance to the motor impairing effects of GHBA and ethanol was assessed (Experiment 2). Administration of 1.0 g/kg GHBA produced a significantly lower impairment in ethanol-tolerant rats than in ethanol-naive rats. Similarly, administration of 3.5 g/kg ethanol induced a significantly lower impairment in GHBA-tolerant rats than in GHBA-naive rats. The presence of cross-tolerance between GHBA and ethanol is discussed in terms of common pathways of neuroadaptation to chronic GHBA and ethanol.

The effect of the dihydropyridine calcium channel antagonist, darodipine, on ethanol withdrawal syndrome was examined in rats made dependent on ethanol by repeated ethanol administration for six consecutive days. Chronic co-administration of darodipine prevented the severity of ethanol withdrawal signs in a dose-dependent fashion. By contrast, acute administration of darodipine during the ethanol withdrawal phase was ineffective in reversing the withdrawal symptoms. The results suggest that the presence of darodipine in the central nervous system during the adaptative responses to ethanol is necessary to reduce the severity of the withdrawal syndrome. They also provide further evidence for a potential clinical usefulness of dihydropyridine calcium channel blockers in treatment of ethanol withdrawal.