Effect of ethanol on gamma-vinyl GABA-induced GABA accumulation in the substantia nigra and on synaptosomal GABA content in six rat brain regions

Alcohol use among patients with epilepsy in western China. A hospital-based study

AMIS: Alcohol consumption has multiple negative consequences for people with epilepsy, including precipitation of seizure or status epilepticus, worsening of seizure control, increased adverse effects of anti-seizure medications, increased sudden unexpected death in epilepsy, and premature mortality. The aim of this study was to investigate alcohol use and explore the sociodemographic and clinical factors associated with alcohol use among patients with epilepsy in western China.

METHODS

A face-to-face questionnaire on alcohol use was conducted at Sichuan Provincial People's Hospital from December 2020 to June 2021. All adult patients who came to our epilepsy center (inpatient and outpatient) were invited to participate in this study. Logistic regression was used to evaluate the possible risk factors associated with alcohol use within the last 12 months.

RESULTS

A total of 425 patients completed this study, 24.2% of patients with epilepsy had used alcohol within the last 12 months, being male and having a history of alcohol use were independently associated factors. Among patients who had used alcohol within the last 12 months, 52.4% complained of worsening of seizure control, heavy alcohol use, and frequent alcohol use were independently associated with worsening of seizure control after alcohol use in patients with epilepsy.

CONCLUSION

This study revealed that the rate of alcohol use among patients with epilepsy was high. Male patients with a history of alcohol use were more prone to alcohol use after a diagnosis of epilepsy. Heavy alcohol use and frequent alcohol use were independently associated with worsening of seizure control after alcohol use in patients with epilepsy. Patient education on the destructive effects of alcohol use is needed for patients with epilepsy.

A multidisciplinary approach to the management of liver disease and alcohol disorders in psychiatric settings (Review)

Society is burdened with the uncontrolled use of alcohol, an ongoing issue, with a substantial associated morbidity and a pressing economical reverberation. It is inevitable that a series of psychiatric patients who display alcohol disorders will be admitted to hospital while also suffering from health conditions, such as liver disease, due to the consumption of alcohol. Managing comorbid patients in a psychiatric facility is a delicate matter that requires a collaborative team. The aim of this systematic paper is to highlight the following: The possibility of treating alcohol use disorder (AUD) and alcohol withdrawal syndrome (AWS) overlapping alcohol liver disease (ALD) within a psychiatric institution, and the importance of a collaborative multidisciplinary team; correctly dosing psychoactive medication when metabolism is affected by ALD; deciding when is it necessary to seek a transfer to a general hospital. Prescribing medication in patients suffering from ALD is still a not a fully documented territory. Protein binding, metabolism, bioavailability, extraction ratios, excretion route, and half-life must be taken into consideration as well as frequently repeating liver panels. Studies suggest that short-acting benzodiazepines are preferred over their alternatives when treating AWS in ALD. All anticonvulsants can be used in patients with decompensated liver disease with caution, although newer generation antiepileptic agents should be first line. Propofol is favored to benzodiazepines or opioids in the case of decompensated cirrhosis. Patients with ALD are likely to be further compromised by the potential hepatocytotoxicity of some pharmacological agents. On that account, having an integrated perspective of the medical case while taking into consideration the underlying illness as well as possible drug interaction is crucial in treating AUD or AWS in a psychiatric institution.

Electrically evoked synaptosomal amino acid transmitter release in human brain in alcohol misuse

Severe chronic alcohol misuse leads to neuropathological changes in human brain, with the greatest neuronal loss in the dorsolateral prefrontal cortex. In this region, GABA(A) receptors are selectively upregulated, and show altered subunit expression profiles only in alcoholics without comorbid disease, whereas glutamate(NMDA) subunit expression profiles are selectively downregulated only in alcoholics with comorbid cirrhosis of the liver. To determine whether these outcomes might be conditional on synaptic transmitter levels, evoked release was studied in well-characterized synaptosome suspensions preloaded with L-[(3)H]glutamate and [(14)C]GABA and stimulated electrically (±10 V contiguous square waves, 0.4 ms, 100 Hz, 1.5 min) with and without Ca(2+). Stimulation elicited brief peaks of both radioisotopes that were larger in the presence of Ca(2+) ions (p < 0.01). A repeat stimulus evoked a second, smaller (p < 0.01) peak. Ca(2+)-dependent L-[(3)H]glutamate release, but not [(14)C]GABA release, was higher overall in alcoholics than in controls (p < 0.05). With comorbid cirrhosis, L-[(3)H]glutamate release showed a graded response, whereas [(14)C]GABA release was lowest in noncirrhotic alcoholics. Release patterns did not differ between cortical regions, or between males and females. Neither age nor postmortem interval was a significant confounder. The released transmitters may differentially alter receptor profiles on postsynaptic cells.

Alcohol consumption, unprovoked seizures, and epilepsy: a systematic review and meta-analysis

PURPOSE

The purpose of this research was to analyze and quantify the association between alcohol consumption and epilepsy as an independent disease, in part operationalized by the occurrence of unprovoked seizures, as well as to examine causality.

METHODS

Systematic review, meta-analysis.

RESULTS

A strong and consistent association between alcohol consumption and epilepsy/unprovoked seizures was found with an overall relative risk (RR) of 2.19 [95% confidence interval (CI) 1.83-2.63]. There was a dose-response relationship between the amount of alcohol consumed daily and the probability of the onset of epilepsy. Individuals consuming an average of four, six, and eight drinks daily had RRs of 1.81 (95% CI 1.59-2.07), 2.44 (95% CI 2.00-2.97), and 3.27 (95% CI 2.52-4.26), respectively, compared to nondrinkers. Several pathogenic mechanisms for the development of epilepsy in alcohol users were identified. Most of the relevant studies found that a high percentage of alcohol users with epilepsy would qualify for the criteria of alcohol dependence. Data were inconclusive regarding a threshold for the effect of alcohol, but most studies suggest that the effect may only hold for heavy drinking (four and more drinks daily).

DISCUSSION

The relationship between alcohol consumption and epilepsy and unprovoked seizures was quantified and several pathogenic mechanisms were suggested, although none of them has been proven to be the unique causative pathway for epilepsy. Certain limitations underlying this study require further research to clarify the outstanding statistical issues and pathogenesis of epilepsy in heavy drinkers.

Molecular pathogenesis of alcohol withdrawal seizures: the modified lipid-protein interaction mechanism

The phrase alcohol withdrawal seizures (AWS) refers to seizures that result from the withdrawal of alcohol after a period of chronic alcohol administration. A mechanism of AWS is postulated, namely the modified lipid-protein interaction (MLPI) mechanism. This hypothesis is based upon an evaluation of the mechanisms of membrane fluidity, calcium channels, gamma-aminobutyric acid (GABA) and glutamate in the molecular pathogenesis of AWS. The mechanism hypothesizes that acute ethanol treatment alters the neuronal membrane lipids which then perturbs protein events, such as affecting the GABAA receptors, NMDA receptors and voltage-dependent Ca2+ channels synergistically or in combination. Subsequent adaptations in these systems occur after prolonged administration of ethanol. A sudden withdrawal of ethanol then leads to hyperexcitability which results in AWS.

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

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

Sensitivity of postsynaptic GABAB receptors on hippocampal CA1 and CA3 pyramidal neurons to ethanol

Baclofen-induced hyperpolarization of hippocampal CA1 and CA3 pyramidal neurons was examined to assess the impact of ethanol on postsynaptic GABAB receptors. These receptors activate outward K+ currents via a pertussis toxin-sensitive G protein cascade to reduce membrane potential during the slow inhibitory postsynaptic potential. This inhibitory action may play a role in ethanol intoxication and withdrawal excitability. In both types of pyramidal neurons, baclofen applied consecutively in increasing concentrations caused concentration dependent hyperpolarization. There were no significant differences in resting membrane potential, input resistance, maximum baclofen-induced hyperpolarization or EC50 between CA1 and CA3 neurons, although slope values were significantly smaller in the former neurons. These parameters were not significantly changed in the presence of ethanol 10-100 mM. Chronic ethanol treatment (12 days) sufficient to induce physical dependence also did not shift sensitivity or maximum response to baclofen in CA1 neurons. These results suggest that GABAB receptors in this model are essentially insensitive to ethanol and do not confirm our earlier preliminary observation of a possible down-regulation of postsynaptic GABAB receptor function by chronic ethanol treatment.

Acamprosate modulates synaptosomal GABA transmission in chronically alcoholised rats

Male Sprague-Dawley rats were pulmonary alcoholised for 30 days. Six were treated with acamprosate (400 mg/kg/day, PO) during alcoholisation. The control nonalcoholised group also received acamprosate (400 mg/kg/day, PO) during the 30 days. At the end of the experiment, brains areas (cortex, hippocampus, thalamus, striatum, and olfactory bulbs) were dissected for the study of synaptosomal 3H-GABA uptake. In another experiment, GABA levels were determined in the same areas using HPLC with electrochemical detection. Blood ethanol levels were also measured during alcoholisation. Acamprosate treatment did not modify blood ethanol levels. In cortex and olfactory bulbs, alcoholisation increased 3H-GABA uptake (Vmax) with an increase in the affinity (Km). 3H-GABA uptake was not affected by alcoholisation in other brain areas. In hippocampus and thalamus, acamprosate treatment enhanced 3H-GABA uptake (Vmax) only in alcoholised rats. Moreover, in thalamus, alcoholisation enhanced GABA levels. The effect of alcohol and acamprosate on GABA presynaptic events is discussed and it is concluded that the action of ethanol and acamprosate on GABA transport could be, in part, responsible for the modulation by acamprosate treatment of ethanol behaviour.

Effects of acute and chronic ethanol treatment on pre- and postsynaptic responses to baclofen in rat hippocampus

Interactions between the GABAB receptor and acute or chronic ethanol treatment were studied using extracellular and intracellular electrophysiological recording techniques. Bath application of the GABAB receptor agonist, (-)-baclofen (0.1-100 microM) induced concentration-dependent inhibition of extracellularly recorded dendritic excitatory postsynaptic potentials (EPSPs) in the CA1 region of hippocampal slices. Responses to baclofen were unchanged relative to control either by simultaneous application of ethanol (10-60 mM) or by previous chronic ethanol exposure. The membrane potential of CA1 pyramidal neurons was reversibly hyperpolarized an average of 5 mV by pressure ejection of baclofen (1 mM). Bath application of ethanol (30 mM) alone occasionally caused a small depolarization of resting membrane potentials in CA1 neurons but failed to increase hyperpolarizing responses to pressure-ejected baclofen. However, in slices from chronic ethanol-treated animals hyperpolarizing responses to bath-applied baclofen (10 microM) were reduced by approximately 30% relative to controls. These results suggest that GABAB-mediated responses in CA1 hippocampal pyramidal neurons are relatively resistant to the acute effects of ethanol, but that continuous exposure to ethanol sufficient to induce physical dependence may evoke an adaptive reduction in some GABAB receptor mediated responses.

The alcohol tolerant and alcohol nontolerant rat lines selected for differential sensitivity to ethanol: a tool to study mechanisms of the actions of ethanol

Genetic selection work conducted in the Research Laboratories of State Alcohol Company (Alko Ltd), Helsinki, Finland, has resulted in the establishment of the ethanol sensitive Alcohol Nontolerant (ANT) and ethanol insensitive Alcohol Tolerant (AT) rat lines which differ in their sensitivity to ethanol induced motor impairment. These lines have been used in attempts to identify the mechanisms controlling ethanol induced motor impairment. The Alcohol Tolerant rats show a lower sensitivity to ethanol induced motor impairment on a tilting plane over a wide range of doses, but the lines do not differ in all behavioral measures of ethanol sensitivity. Furthermore, the Alcohol Tolerant line shows a higher capacity to develop acute tolerance and less calm behaviour, which may contribute to the line difference. Neurochemical work has shown differences in the functioning and sensitivity to ethanol of the catecholaminergic and GABAergic systems in the two lines, suggesting a role for both of these systems in the control of ethanol induced motor impairment.

GABA turnover in the brain of rat lines developed for differential ethanol-induced motor impairment

The role of GABAergic neurons in the differential sensitivity to ethanol between the AT (Alcohol Tolerant) and ANT (Alcohol Nontolerant) rat lines developed for low and high degree of motor impairment from ethanol, was studied by comparing the effect of ethanol (2 or 4 g/kg, IP) on GABA turnover in different regions of the brain in these rat lines. GABA turnover was estimated from the accumulation of GABA after inhibition of GABA aminotransferase with aminooxyacetic acid (AOAA, 50 mg/kg, IP) given 10 min after administration of ethanol. The rats were killed two hours after the AOAA treatment with focused microwaves. The concentrations of GABA, aspartate, glutamate, glutamine and taurine were analyzed with HPLC. The saline-treated ANT rats were found to have a higher concentration of GABA in the striatum and a higher rate of GABA accumulation in the cerebellum than the AT rats. Ethanol suppressed the accumulation of GABA in both lines, but the suppression was significantly greater in the AT rats than in the ANT rats. In specific regions, this line difference was significant in the cerebral cortex and cerebellum with the higher ethanol dose. No line differences were found in the brain or tail blood ethanol concentration. AOAA increased the concentration of glutamine, decreased that of aspartate and glutamate, and did not modify that of taurine. The AOAA-induced changes in the concentrations of these amino acids were, however, minor relative to those found in the concentrations of GABA. The results that GABAergic mechanisms are involved in the differential sensitivity to the motor-impairing effects of ethanol between the AT and ANT rats.