Discriminative stimulus effects of tiagabine and related GABAergic drugs in rats

Gabapentin Reduces Alcohol Intake in Rats by Regulating NF-κB Signaling Pathway Via PPAR γ

AIMS

Increasing preclinical and clinical reports have demonstrated the efficacy of gabapentin (GBP) in treating alcohol use disorder (AUD). However, the mechanism of the effects of GBP in AUD is largely unknown. Herein, we sought to investigate the effect of GBP in a rat model of AUD and explore the underlying mechanism.

METHODS

The intermittent access to 20% ethanol in a 2-bottle choice (IA2BC) procedure was exploited to induce high voluntary ethanol consumption in rats. The rats were treated daily for 20 days with different doses of GBP, simultaneously recording ethanol/water intake. The locomotor activity and grooming behavior of rats were also tested to evaluate the potential effects of GBP on confounding motor in rats. The levels of IL-1β and TNF-α in serum and hippocampus homogenate from the rats were detected by using ELISA. The expressions of peroxisome proliferator-activated-receptor γ (PPAR-γ) and nuclear factor-κB (NF-κB) in the hippocampus were determined by immunofluorescence and western blot.

RESULTS

GBP reduced alcohol consumption, whereas increased water consumption and locomotor activity of rats. GBP was also able to decrease the levels of IL-1β and TNF-α in both serum and hippocampus, in addition to the expression of NF-κB in the hippocampus. Furthermore, these effects attributed to GBP were observed to disappear in the presence of bisphenol A diglycidyl ether (BADGE), a specific inhibitor of PPAR-γ.

CONCLUSIONS

Our findings revealed that GBP could activate PPAR-γ to suppress the NF-κB signaling pathway, contributing to the decrease of ethanol consumption and ethanol-induced neuroimmune responses.

Baclofen for alcohol withdrawal

BACKGROUND

Alcohol withdrawal syndrome (AWS) is a distressing and life-threatening condition that usually affects people who are alcohol dependent when they discontinue or decrease their alcohol consumption. Baclofen shows potential for rapidly reducing symptoms of severe AWS in people with alcoholism. Treatment with baclofen is easy to manage and rarely produces euphoria or other pleasant effects, or craving for the drug. This is an updated version of the original Cochrane Review first published in 2011 and last updated in 2017.

OBJECTIVES

To assess the efficacy and safety of baclofen for people with AWS.

SEARCH METHODS

We updated our searches of the following databases to June 2019: the Cochrane Drugs and Alcohol Group Specialised Register, CENTRAL, PubMed, Embase, and CINAHL. We also searched registers of ongoing trials. We handsearched the references quoted in the identified trials, and sought information from researchers, pharmaceutical companies, and relevant trial authors about unpublished or uncompleted trials. We placed no restrictions on language.

SELECTION CRITERIA

We included all randomised controlled clinical trials (RCTs) evaluating baclofen versus placebo or any other treatment for people with AWS. We excluded uncontrolled, non-randomised, or quasi-randomised trials. We included both parallel group and cross-over studies.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included four RCTs with 189 randomised participants (one RCT new for this update). None of the included studies reported the primary outcomes of alcohol withdrawal seizures, alcohol withdrawal delirium, or craving. For the comparison of baclofen and placebo (1 study, 31 participants), there was no evidence of a difference in Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised (CIWA-Ar) scores in eight-hour periods from days one to five (very low-quality evidence). For the comparison of baclofen and diazepam (2 studies, 85 participants), there was no evidence of a difference in change from baseline to days 10 to 15 on CIWA-Ar scores (very low-quality evidence, meta-analysis was not performed due to insufficient data). In one study (37 participants), there was no evidence of a difference in participants with at least one adverse event (risk difference (RD) 0.00, 95% confidence interval (CI) -0.10 to 0.10; very low-quality evidence), dropouts (RD 0.00, 95% CI -0.10 to 0.10; very low-quality evidence), and dropouts due to adverse events (RD 0.00, 95% CI -0.10 to 0.10; very low-quality evidence). For the comparison of baclofen and chlordiazepoxide (1 study, 60 participants), there was no evidence of a difference in difference from baseline to nine-day decremental fixed-dose intervention: CIWA-Ar scores (mean difference (MD) 1.00, 95% CI 0.70 to 1.30; very low-quality evidence), global improvement (MD 0.10, 95% CI -0.03 to 0.23; very low-quality evidence), 14/60 participants with adverse events (RD 2.50, 95% CI 0.88 to 7.10; very low-quality of evidence), dropouts (RD 0.00, 95% CI -0.06 to 0.06; very low-quality evidence), and dropouts due to adverse events (RD 0.00, 95% CI -0.06 to 0.06; very low-quality evidence). None of the RCTs provided information on random sequence generation or allocation concealment, therefore, we assessed them at unclear risk of bias. Two RCTs were not of double-blind design and had a high risk of bias in blinding (Addolorato 2006; Girish 2016). One RCT had more than 5% dropouts with high risk of attrition bias (Lyon 2011). We could not assess reporting bias as none of the prepublished protocols were available.

AUTHORS' CONCLUSIONS

No conclusions can be drawn about the efficacy and safety of baclofen for the management of alcohol withdrawal because we found insufficient and very low-quality evidence.

Baclofen for alcohol withdrawal

BACKGROUND

Baclofen shows potential for rapidly reducing symptoms of severe alcohol withdrawal syndrome (AWS) in people with alcoholism. Treatment with baclofen is easy to manage and rarely produces euphoria or other pleasant effects, or craving for the drug. This is an updated version of the original Cochrane Review published in 2015, Issue 4.

OBJECTIVES

To assess the efficacy and safety of baclofen for people with AWS.

SEARCH METHODS

We updated our searches of the following databases to March 2017: the Cochrane Drugs and Alcohol Group Specialised Register, CENTRAL, PubMed, Embase, and CINAHL. We also searched registers of ongoing trials. We handsearched the references quoted in the identified trials, and sought information from researchers, pharmaceutical companies, and relevant trial authors about unpublished or uncompleted trials. We placed no restrictions on language.

SELECTION CRITERIA

We included all randomised controlled clinical trials (RCTs) evaluating baclofen versus placebo or any other treatment for people with AWS. We excluded uncontrolled, non-randomised, or quasi-randomised trials. We included both parallel group and cross-over studies.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included three RCTs with 141 randomised participants. We did not perform meta-analyses due to the different control interventions. For the comparison of baclofen and placebo (1 study, 31 participants), there was no significant difference in Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised (CIWA-Ar) scores (very low quality evidence). For the comparison of baclofen and diazepam (1 study, 37 participants), there was no significant difference in CIWA-Ar scores (very low quality evidence), adverse events (risk difference (RD) 0.00, 95% confidence interval (CI) -0.10 to 0.10; very low quality evidence), dropouts (RD 0.00, 95% CI -0.10 to 0.10; very low quality evidence), and dropouts due to adverse events (RD 0.00, 95% CI -0.10 to 0.10; very low quality evidence). For the comparison of baclofen and chlordiazepoxide (1 study, 60 participants), there was no significant difference in CIWA-Ar scores (mean difference (MD) 1.00, 95% CI 0.70 to 1.30; very low quality evidence), global improvement (MD 0.10, 95% CI -0.03 to 0.23; very low quality evidence), adverse events (RD 2.50, 95% CI 0.88 to 7.10; very low quality of evidence), dropouts (RD 0.00, 95% CI -0.06 to 0.06; very low quality evidence), and dropouts due to adverse events (RD 0.00, 95% CI -0.06 to 0.06; very low quality evidence).

AUTHORS' CONCLUSIONS

No conclusions can be drawn about the efficacy and safety of baclofen for the management of alcohol withdrawal because we found insufficient and very low quality evidence.

Comparing the discriminative stimulus effects of modulators of GABAA receptors containing α4-δ subunits with those of gaboxadol in rats

RATIONALE

Gaboxadol is a selective agonist at γ-aminobutyric acidA (GABAA) receptors that contain α4-δ subunits, and it produces anxiolytic and sedative effects. Although adverse effects preclude its clinical use, its mechanism of action suggests that those receptors might provide novel therapeutic targets, particularly for modulators of those GABAA receptor subtypes, by retaining therapeutic effects of gaboxadol and not adverse effects.

OBJECTIVES

The current study compared discriminative stimulus effects of gaboxadol with those of modulators acting at GABAA receptors containing α4-δ subunits.

MATERIALS

Eight rats discriminated 5.6 mg/kg gaboxadol from vehicle while responding under a fixed - ratio 10 schedule for food. Modulators acting at GABAA receptors containing α4-δ subunits (pregnanolone, ethanol, and flumazenil) and receptors that do not contain those subunits (midazolam) were studied alone; pregnanolone and ethanol were also combined with gaboxadol. In addition, gaboxadol was studied in separate groups discriminating 0.32 mg/kg midazolam, 3.2 mg/kg pregnanolone, or 0.75 g/kg ethanol from vehicle.

RESULTS

Gaboxadol produced ≥80 % gaboxadol-lever responding and did not alter rates. No other drug produced, on average, ≥80 % drug-lever responding up to doses that decreased rates, although 1.78 mg/kg midazolam produced 32 % gaboxadol-lever responding. Ethanol and pregnanolone did not enhance the effects of gaboxadol. Rats discriminating midazolam, pregnanolone, or ethanol from vehicle responded predominantly on the vehicle lever after receiving gaboxadol.

CONCLUSIONS

Drugs that modulate GABAA receptors containing α4-δ subunits neither mimicked nor enhanced the discriminative stimulus effects of gaboxadol, indicating that at least some effects of gaboxadol are not shared with modulators of that GABAA receptor subtype.

Gabapentin potentiates sensitivity to the interoceptive effects of alcohol and increases alcohol self-administration in rats

Gabapentin, a drug used in the treatment of epileptic seizures and neuropathic pain, has shown efficacy in the treatment of alcohol dependence. Moreover, given that gabapentin is used in the general population (e.g., non-dependent individuals, social drinkers), we sought to utilize preclinical assessments to examine the effects of gabapentin on sensitivity to moderate alcohol doses and alcohol self-administration in rats with a history of moderate drinking. To this end, we assessed whether gabapentin (0, 10, 30, 120 mg/kg, IG) pretreatment alters sensitivity to experimenter- and self-administered alcohol, and whether gabapentin alone has alcohol-like discriminative stimulus effects in rats trained to discriminate alcohol dose (1 g/kg, IG) vs. water. Second, we assessed whether gabapentin (0, 10, 30, 60 mg/kg, IG) would alter alcohol self-administration. Gabapentin pretreatment potentiated the interoceptive effects of both experimenter-administered and self-administered alcohol in discrimination-trained rats. Additionally, the highest gabapentin doses tested (30 and 120 mg/kg) were found to have partial alcohol-like discriminative stimulus effects when administered alone (e.g., without alcohol). In the self-administration trained rats, gabapentin pretreatment (60 mg/kg) resulted in an escalation in alcohol self-administration. Given the importance of interoceptive drug cues in priming and maintaining self-administration, these data define a specific behavioral mechanism (i.e., potentiation of alcohol effects) by which gabapentin may increase alcohol self-administration in non-dependent populations.

Baclofen for alcohol withdrawal

BACKGROUND

The treatment baclofen shows potential for rapidly reducing symptoms of severe alcohol withdrawal syndrome (AWS) in people with alcoholism. Treatment with baclofen is easy to manage and rarely produces euphoria or other pleasant effects, or craving for the drug. This is an updated version of the original Cochrane review published in Issue 2, 2013.

OBJECTIVES

To assess the efficacy and safety of baclofen for people with AWS.

SEARCH METHODS

We searched the Cochrane Drugs and Alcohol Group Specialised Register (searched 13 January 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 1), MEDLINE (1966 to January 2015), EMBASE (1980 to January 2015), and CINAHL (1982 to January 2015). We also searched registers of ongoing trials, including ClinicalTrials.gov, the ISRCTN registry, and the European Clinical Trials Database. At the same time, we handsearched the references quoted in the identified trials, and sought information from researchers, pharmaceutical companies, and relevant trial authors about unpublished or uncompleted trials. We placed no restrictions on language.

SELECTION CRITERIA

We included all randomised controlled clinical trials (RCTs) evaluating baclofen versus placebo or any other treatment for people with AWS. We excluded uncontrolled, non-randomised, or quasi-randomised trials. We included both parallel group and cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed references retrieved for possible inclusion. Any disagreements were resolved by an independent party. We contacted study authors for additional information where needed. We collected adverse effects information from the trials.

MAIN RESULTS

Two RCTs with a total of 81 participants were eligible according to the inclusion criteria. One study suggested that both baclofen and diazepam significantly decreased the Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised (CIWA-Ar) score, without any significant difference between the two interventions. The other study showed no significant difference in CIWA-Ar score between baclofen and placebo, but a significantly decreased dependence on high-dose benzodiazepines with baclofen compared to placebo. Only one study reported on the safety of baclofen, without any side effects.

AUTHORS' CONCLUSIONS

The evidence for recommending baclofen for AWS is insufficient. We therefore need more well-designed RCTs to prove its efficacy and safety.

GABA and glutamate pathways are spatially and developmentally affected in the brain of Mecp2-deficient mice

Proper brain functioning requires a fine-tuning between excitatory and inhibitory neurotransmission, a balance maintained through the regulation and release of glutamate and GABA. Rett syndrome (RTT) is a rare genetic disorder caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene affecting the postnatal brain development. Dysfunctions in the GABAergic and glutamatergic systems have been implicated in the neuropathology of RTT and a disruption of the balance between excitation and inhibition, together with a perturbation of the electrophysiological properties of GABA and glutamate neurons, were reported in the brain of the Mecp2-deficient mouse. However, to date, the extent and the nature of the GABA/glutamate deficit affecting the Mecp2-deficient mouse brain are unclear. In order to better characterize these deficits, we simultaneously analyzed the GABA and glutamate levels in Mecp2-deficient mice at 2 different ages (P35 and P55) and in several brain areas. We used a multilevel approach including the quantification of GABA and glutamate levels, as well as the quantification of the mRNA and protein expression levels of key genes involved in the GABAergic and glutamatergic pathways. Our results show that Mecp2-deficient mice displayed regional- and age-dependent variations in the GABA pathway and, to a lesser extent, in the glutamate pathway. The implication of the GABA pathway in the RTT neuropathology was further confirmed using an in vivo treatment with a GABA reuptake inhibitor that significantly improved the lifespan of Mecp2-deficient mice. Our results confirm that RTT mouse present a deficit in the GABAergic pathway and suggest that GABAergic modulators could be interesting therapeutic agents for this severe neurological disorder.

Baclofen for alcohol withdrawal

BACKGROUND

The treatment baclofen can rapidly reduce symptoms of severe alcohol withdrawal syndrome (AWS) in alcoholic patients, with a significant reduction in the cost. Baclofen is easy to manage, and rare euphoria, craving and other pleasant effects are reported by patients treated with baclofen.

OBJECTIVES

To assess the efficacy and safety of baclofen for patients with AWS.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (October 2012), MEDLINE (1966 to October 2012), EMBASE (1980 to October 2012) and CINAHL (1982 to October 2012). We also searched registers of ongoing trials, for example ClinicalTrials.gov, Controlled-trials.com, EUDRACT, etc. At the same time, we handsearched the references quoted in the identified trials, and contacted researchers, pharmaceutical companies and relevant trial authors seeking information about unpublished or uncompleted trials. All searches included the non-English language literature.

SELECTION CRITERIA

All randomized controlled clinical trials (RCTs) evaluating baclofen versus placebo or any other treatment for patients with AWS. Uncontrolled, non-randomized or quasi-randomized trials were excluded. Both parallel group and cross-over design were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed references retrieved for possible inclusion. All disagreements were resolved by an independent party. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

We identified a total of 113 references from all electronic databases searched excluding duplicates. After screening of titles and abstracts, full papers of 10 studies were obtained and assessed for eligibility. Finally, two RCTs with 81 participants were eligible according to the inclusion criteria. Regarding the efficacy, one study suggested that both baclofen and diazepam significantly decreased the Clinical Institute Withdrawal Assessment of Alcohol Scale Revised (CIWA-Ar) score, without any significant difference between the two interventions. The other study showed no significant difference in CIWA-Ar score between baclofen and placebo but a significantly decreased dependence on high-dose benzodiazepines with baclofen compared to placebo. Meanwhile, only one study reported the safety outcomes and there were no side effects in either the baclofen or diazepam groups.

AUTHORS' CONCLUSIONS

The evidence for recommending baclofen for AWS is insufficient. More well designed RCTs are needed to prove its efficacy and safety.

Use of the light-dark box to compare the anxiety-related behavior of virgin and postpartum female rats

Postpartum female rodents are less anxious than diestrous virgins and this difference contributes to dams' ability to adequately care for pups and defend the nest. Low postpartum anxiety has been observed in many behavioral paradigms but the results of previous studies using the light-dark box have been inconsistent. We here reexamined the usefulness of the light-dark box to assess differences between postpartum and diestrous virgin female rats in their anxiety-related behavior. We found a significant effect of reproductive state, such that dams spent more time in the light chamber than did diestrous virgins. This difference required recent physical contact with pups because a four-hour separation from pups reduced dams' time spent in the light chamber by half, similar to what we previously found for litter-separated dams tested in an elevated plus maze. We then examined if dams' low-anxiety behavior in the light-dark box depends on high GABA(A) receptor activity by inhibiting the receptor at different binding sites using (+)-Bicuculline to target the GABA site, FG-7142 to target the benzodiazepine site, and pentylenetetrazol to target the picrotoxin site. Only pentylenetetrazol was consistently anxiogenic in dams, while having little effect in diestrous virgins. Thus, the light-dark box can be a useful paradigm to study differences between postpartum and diestrous virgin female rats in their anxiety-related behaviors, and this difference is influenced by dams' recent contact with pups and GABA(A) receptor neurotransmission particularly affected by activity at the picrotoxin site.

Baclofen for alcohol withdrawal

BACKGROUND

The treatment of baclofen can rapidly reduce symptoms of severe alcohol withdrawal syndrome (AWS) in alcoholic patients, with a significant reduction in the cost. Baclofen is easily manageable, what's more, no patient treated with baclofen reported euphoria or other pleasant effects caused by the drug and no subject reported any degree of craving for the drug.

OBJECTIVES

To assess the efficacy and safety of baclofen for patients with alcohol withdrawal syndrome.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (September 2010), MEDLINE (1966 to September 2010), EMBASE (1980 to September 2010), and CINAHL (1982 to September 2010). We also searched the following registers of ongoing trials, e.g. Clinicaltrials.gov, Controlled trials.com, EUDRACT, etc. At the same time, we handsearched the references quoted in the identified trials, contact researchers, pharmaceutical companies and relevant trial authors seeking information about unpublished or incomplete trials. All searches included non-English language literature.

SELECTION CRITERIA

All randomised controlled clinical trials (RCTs) evaluating baclofen versus placebo or any other treatment for patients with AWS. Uncontrolled, non-randomised or quasi-randomised trials were excluded. Both parallel group and cross-over design were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed references retrieved for possible inclusion. All disagreements were resolved by an independent party. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

We identified a total of 82 references from all electronic databases searched excluding duplicate. After screening of titles and abstracts, full papers of 7 studies were obtained and assessed for eligibility. Finally, only one study met the inclusion criteria, with 37 participants.

AUTHORS' CONCLUSIONS

The evidence of recommending baclofen for AWS is insufficient. More well designed RCTs are demanded to further prove its efficacy and safety.