Alcohol and alcoholism (Oxford, Oxfordshire). Supplement最新文献

In this study, we examined the quantity and quality of G proteins in membrane preparations from cortical regions (frontal, parietal, temporal and occipital cortex) in post-mortem brains obtained from subjects with chronic alcoholism and controls matched with respect to age and post-mortem delay (PMDT). Immunoblot analysis showed that the level of GsH alpha (52 kDa) was significantly decreased in temporal cortical membranes from alcoholics compared with controls, while no differences were observed in the amount of any G protein in frontal, parietal and occipital regions. Additionally, ethanol enhanced photoaffinity guanine nucleotide binding to both G alpha and Gi/o alpha in human cortical membranes. The percentage of increase in ethanol-stimulated photoaffinity GTP labeling of Gs alpha and Gi/o alpha was decreased in alcoholic patients in all cortical regions. These observations indicated that subsensitivities to ethanol-induced stimulation in G protein may contribute to impaired trans-signaling in cortical membranes of chronic alcoholics.

The acute effects of ethanol on the function of G protein in rat cerebral cortical membranes were examined using immunoblotting and photosensitive GTP labeling. Ethanol potentiated GppNHp-dependent activation of adenylyl cyclase and inhibition of forskolin-stimulated activity of the enzyme in corticol membranes from Wistar rats. It also enhanced guanine nucleotide binding to Gs and Gi as estimated by photoaffinity labeling. However, ethanol had no effects on the contents of Gs/alpha, Gi(1) alpha and Gi(2) alpha, and G beta subunits. While it potentiated Gi-mediated inhibition of adenylyl cyclase in Wistar rats, ethanol had no effect on the inhibitory regulation of the enzyme in the membranes from Fischer 344 rats. These results suggest that ethanol in vitro enhances both Gs and Gi functions in cerebral cortical membranes from Wistar rats and that the Gi function in the cerebral cortex may be differentially regulated by ethanol in Wistar and Fischer 344 rats.

We studied the effect of administration of a mixture of alanine and glutamine on the inhibition of liver regeneration caused by alcohol in rats undergoing partial hepatectomy 6 weeks after the start of alcohol administration. DNA synthesis was inhibited 24 hr after partial hepatectomy in rats given alcohol, but treatment with alanine and glutamine partially prevented this inhibition. To identify the mechanism of this effect, polyamine metabolism was studied. Administration of alcohol or alanine plus glutamine had no effect on the activity of ornithine decarboxylase, a rate-limiting enzyme of polyamine metabolism. In the liver, of the three polyamines, only the spermine concentration changed significantly. It decreased during long-term administration of alcohol, and this decrease was prevented by treatment with alanine and glutamine. The level of N(1)-acetylspermidine, the acetylated product of spermidine, was increased by alcohol, and its elevation was significantly less when alanine and glutamine were given. Hepatic spermidine/spermine N(1)-acetyltransferase, the key enzyme of polyamine acetylation, was induced by long-term administration of alcohol, and this induction was suppressed by alanine plus glutamine. The results suggest that treatment with alanine and glutamine can help to prevent the inhibition of liver regeneration caused by alcohol by maintaining the spermine level and suppressing the acetylation of spermidine.

Polymorphic alleles of three genes (GSTMl, CYP1A1 and ApoB) were analysed in the context of the relationship between alcohol and liver diseases. DNAs were prepared from whole blood samples of 84 male controls, 71 male patients with alcoholic liver diseases. PCR and related techniques were used for detection of these polymorphic loci. The frequency of GSTMl gene deletion was significantly higher in the patients with alcoholic liver diseases than in controls (P < 0.05), whereas the frequencies of the genotypes (A, AB, B) in the individuals with GSTMl gene were not statistically different between both groups. In addition, the frequency of GYP1A1*A was found to be significantly higher in alcoholic liver diseases than in controls (P < 0.01). Gene frequencies of ApoB were not different between the two groups. These data suggest that GSTM1 gene deletion and CYP1A1*A gene increase the risk for alcoholic liver diseases.

The DNA-binding activity of the transcription factors AP-1, CREB and OCT was investigated in nuclear extracts of brains from rats undergoing ethanol withdrawal. AP-1 DNA-binding activity but not that of CREB or OCT was increased in the cerebral cortex, hippocampus and cerebellum 15 and 17 hr after ethanol withdrawal. A similar increase in AP-1 binding activity was observed in subcortical structures at 17 hr of ethanol withdrawal. No change in any transcription factor DNA-binding activity was observed in the brain stem. Our results suggest that increased expression of immediate early genes is coupled with an increase in DNA-binding function, indicating that they may play a role in the long-term molecular response to ethanol withdrawal.

The intracellular signal cascade transducing muscarinic-receptor-stimulation to gene expression was investigated in human neuroblastoma SH-SY5Y cells. Naive and ethanol-exposed SH-SU5Y cells were stimulated with carbachol (CCh) and inositol 1,4-5-trisphosphate (IP3), 1,2-diacylglycerol (DAG), and c-fos mRNA levels were analyzed using a radioreceptor assay (IP3) thin-layer chromatography (DAG) and Northern blot (c-fos mRNA). Application of the muscarinic agonist CCh induced a rapid increase in (IP3), peaking within seconds after the CCh-addition. There was also an accumulation of DAG reaching maximum after 5 min of receptor-stimulation. Stimulation with CCh also induced expression of the immediate-early gene c-fos in these cells. These events were mediated via muscarinic M1 receptors and the inhibitory effects of H7, staurosporin, and RO31-7549 on the c-fos expression indicated that it was mediated via protein kinase C. Acute exposure to 100 mM ethanol inhibited the formation of IP3 and the expression of c-fos. These effects were due to an increase in the EC50 of CCh for the events. Exposure to 100 mM ethanol for 4 days caused a potentiation of these two events. The EC50 was unaffected but the maximal response was increased. These data indicate that this signal transduction system is inhibited by acute exposure to 100 mM ethanol, an effect that is compensated for after exposure to ethanol for 4 days.

Screening for alcohol abuse in its early phase, and the diagnosis of alcohol-related organ damage by laboratory tests in clinical settings, have often been unreliable. Protein-acetaldehyde adducts may be helpful in trying to solve this problem and hemoglobin, with its acetaldehyde adducts, appears to be a suitable model for studying protein-acetaldehyde adducts as condensation products of acetaldehyde, a harmful metabolite of ethanol. The modification by acetaldehyde alters the chromatographic properties of the hemoglobin molecule, producing a modified form that can be separated from other hemoglobin forms by cation exchange chromatographic techniques. The methods for the separation of hemoglobin acetaldehyde adducts have been improved in recent years, allowing us today to detect in vitro changes in hemoglobin caused by "physiological" concentrations of acetaldehyde and raising the possibility of developing a method suitable for clinical detection of hemoglobin acetaldehyde adducts.

In devising pharmacological treatments for alcohol dependence, attention has to be directed to drugs which manipulate the neurobiological basis of ethanol's reinforcing properties and which do so with an acceptable margin of safety. This paper will review four main issues; the meaning of "craving", the role of serotonin in the neuroregulation of ethanol consumption and the effect of serotonergic drugs on ethanol intake, the role of other neurotransmitter systems, and how pharmacological treatments can be combined with psychosocial approaches.

Natural killer (NK) cells are large granular lymphocytes (LGL) whose functional characteristics play an important immunological role in tumor surveillance, bacterial and viral infections, baematopoiesis, and tissue transplantation. NK cell cytotoxicity is mediated through non-MHC-restricted lysis and by antibody-dependent cellular lysis against NK-sensitive and insensitive targets. Non-MHC restricted lysis of targets can occur when NK cells are in a non-activated state (inherent NK cell cytolytic activity) and following activation by interleukin 2 (IL-2).

Peripheral administration of selective agents for GABAA receptors have been reported to modify ethanol self-administration behaviour. Recently, it has been reported that the dorsal and median raphe may represent potential brain sites for mediating these effects since injection of the GABAA agonist, muscimol, into these sites increased ethanol intake. The aim of the present study was to extend these findings and assess the effect of muscimol, injected into either the dorsal or median raphe, on a range of parameters including ethanol intake, ethanol-induced hypothermia and ethanol-induced suppression of high rates of responding. Wistar rats trained to drink 12% ethanol for 40 mins each day, increased their ethanol consumption, but not water consumption, following injection of 50 ng muscimol into the dorsal raphe. Ethanol intakes returned to baseline levels the day following drug treatment. The same dose injected into the median raphe has been shown to produce a non-selective increase in both water and ethanol intake. Further analysis of this data revealed that the rats tended to avoid the ethanol solution on the day following treatment. A further difference between the dorsal and median raphe was revealed in the ethanol-induced hypothermia experiment. Thus, 10 ng muscimol injected into the median raphe potentiated the hypothermic response induced by intraperitoneal injection of 1.5 g/kg ethanol, whereas injection into the dorsal raphe had no significant effect on this measure. Intraperitoneal injection of 0.5 g/kg ethanol suppressed operant responding for water intake and this behaviour was not altered by dorsal raphe injection of muscimol. Together these results suggest that GABAergic mechanisms within the dorsal raphe represent an important neural site for controlling the ingestion of ethanol, but not that of ethanol intoxication.