Thiamine deficiency in utero alters response to ethanol in adulthood

To determine whether prenatal thiamine deficiency, a frequent concomitant of alcoholism, reduces the response to ethanol during adulthood in the rat as does ethanol exposure in utero (Abel et al. 1981), pregnant Sprague-Dawley rats received either control or thiamine deficient diets together with daily injections of the thiamine antagonist pyrithiamine. At 7 months of age, male offspring were exposed to precisely regulated ethanol vapor concentrations in an inhalation chamber for 24 h and blood ethanol concentrations (BECs) and ethanol-induced intoxication were determined. Prenatally thiamine deficient rats and controls were indistinguishable in terms of appearance, body and liver weights, and the ratios of liver to body weight and brain to liver weight. However, total body water was significantly greater, and BECs and behavioral impairment were decreased, in the experimental rats. These findings indicate that prenatal thiamine deprivation is associated with reduced pharmacologic effect of ethanol as a result of increases in its volume of distribution and rate of metabolism.     

Effect of Short-Term Ethanol Feeding on Rat Testes as Assessed by 31P NMR Spectroscopy, 1H NMR Imaging, and Biochemical Methods

31P Nuclear magnetic resonance (NMR) spectroscopy and 1H NMR imaging were used to examine the effect of short-term ethanol feeding on the rat testis. Weanling rats were pair-fed for 10 weeks either on ethanol containing liquid diet (36% ethanol of total calories) or a diet in which dextrimaltose was isocalorically substituted for the ethanol of the alcohol-containing diet. In vivo 31P NMR of the testes was used to determine the intratesticular pH and the relative concentrations of various phosphorus-containing metabolites. The integrity of the blood-testes barrier was evaluated using 1H NMR imaging following a gadolinium diethylene tetramine pentaacetic acid derivative (Gd-DTPA) administration as a vascular contrast agent. After the completion of NMR studies, the testis and the liver were freeze-clamped to allow for the assay of their adenosine-5'-triphosphate (ATP) contents. Serum was assayed for its content of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alcohol and testosterone. Ethanol feeding resulted in the following: (a) a reduction in the body weight (p less than 0.05), (b) a reduction in the testicular phosphodiesters (PDE) PDE/ATP ratio (p less than 0.05), (c) an increased change in the testis image intensity difference between pre- and post-iv Gd-DTPA images, (c) a reduction in the testicular and hepatic content of ATP, and (d) increased serum levels of AST and ALT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intoxicating effects of lorazepam and barbital in rat lines selected for differential sensitivity to ethanol

The motor impairing effects and plasma concentrations of barbital and lorazepam were studied in the alcohol tolerant (AT) and alcohol non-tolerant (ANT) rat lines developed for low and high sensitivity to motor impairment from ethanol. The mixed (M) line, from which the AT and ANT rats were derived, was also included in the study. Like ethanol, barbital and lorazepam impaired the performance of the ANT rats more than that of the AT rats. The motor performance of the M rats was relatively more impaired after barbital than after lorazepam administration at the same dose used in the AT and ANT rats. At the two latter time points (2.5 and 3.5 h) the sensitive ANT rats had significantly higher serum barbital concentrations than the AT rats. The serum barbital concentrations of the AT and ANT rats did not differ, however, at the two first time points (0.5 and 1.5 h) of the tilting plane tests, although the ANT rats were significantly more intoxicated. The concentrations of lorazepam in plasma do not explain the differential motor impairment either, since the sensitive ANT rats had lower plasma concentrations than the insensitive AT rats. The results, thus, suggest that the selection involved in the development of the AT and ANT lines has not been specific for ethanol. The results also support the idea that ethanol, barbiturates and benzodiazepines have some modes of action in common.     

酒精对骨髓基质细胞成脂与成骨分化的影响

目的观察酒精对小鼠骨髓基质细胞中脂肪细胞特异性基因422(aP2)和Ⅰ型胶原基因表达的影响。方法采用原代骨髓基质细胞体外培养技术,取小鼠双侧股骨骨髓细胞,通过细胞贴壁、分离,获取骨髓基质细胞。以0.09mol/L的酒精浓度作为诱导剂处理细胞。采用完整细胞斑点印迹分子杂交方法检测实验组和对照组细胞中422(aP2)mRNA和Ⅰ型胶原mRNA的表达。结果对实验组和对照组的422(aP2)mRNA的完整细胞斑点印迹扫描值进行比较,实验组中422(aP2)基因杂交信号明显增强,斑点印迹扫描值为7207.8±331.3,对照组斑点印迹扫描值为652.2±62.6,实验组为对照组的11倍,两组比较差异有非常显著性意义(P<0.001)。对实验组和对照组Ⅰ型胶原mRNA的完整细胞斑点印迹扫描值进行比较,实验组基因杂交信号较对照组明显减弱,斑点印迹扫描值为3 567.3±300.9,对照组斑点印迹扫描值为7487.0±488.4,为实验组的2倍,两组比较差异有非常显著性意义(P<0.001)。结论酒精能诱导骨髓基质细胞向脂肪细胞分化,而减少骨髓基质细胞向成骨细胞分化。这可能与酒精性骨坏死的发生机制有关。     

Effects of Ethanol, Chlordiazepoxide, and MK-801 on Performance in the Elevated-Plus Maze and on Locomotor Activity

The effects of ethanol, chlordiazepoxide, and MK-801 on performance in the elevated-plus maze and on activity measured in a circular activity monitor were compared in Sprague-Dawley rats to determine whether these effects of ethanol could be explained by its action on either GABA_A or NMDA receptors. Both ethanol and chlordiarepoxide produced an increase in the time spent in the open arms of the elevated-plus maze and in the ratio of open arm to total arm entries, indicative of an anxiolytic action of these drugs. MK-801 did not alter either the time spent in the open arms or the ratio of open to total arm entries. Chlordiazepoxide and MK-801 produced an increase in total arm entries that suggested that these compounds were increasing locomotor activity. Ethanol also increased total arm entries, but the effect was not statistically reliable. Following habituation to an activity monitor, neither ethanol nor chlordiazepoxide increased activity in this task, whereas MK-801 produced a robust increase in locomotion. Additionally, neither ethanol nor chlordiazepoxide blocked the MK-801-induced locomotor stimulation. The latter finding suggests that the effects of ethanol on GABAA receptors was not Mocking an increased activity level produced by its antagonism of NMDA. Additionally, these results indicate that the anxiolytic and locomotor action of ethanol in rats parallel the effects of a benzodiazepine and not those of an NMDA antagonist. Finally, these results suggest that the consequence of ethanol's antagonism of NMDA receptor function is more restricted than that produced by MK-801.     

Suppression of alcohol and saccharin preference in rats by a novel Ca2+ channel inhibitor,Goe 5438

The effect of the novel 1,4-dihydronaphthyridine Ca²⁺ channel inhibitor Goe 5438 (CI-951) on voluntary ethanol consumption was examined in selectively bred alcohol-preferring (P) rats in a free choice two bottle preference test versus water. Intraperitoneally injected Goe 5438 dose-dependently (5, 10 or 20 µmol/kg, twice daily) inhibited ethanol and increased water intake over the 24 h period (injection day). The drug decreased ethanol preference, originally above 90%, by 6%, 19% and 45% at respective doses, on the injection day. That inhibitory effect of the highest dose of Goe 5438 on ethanol preference remained significant also on days 2 and 3 after injections (–51% and –18%, respectively). Goe 5438, in the highest dose, also tended to decrease granulated chow consumption during the injection day only. To further test whether the inhibition of ethanol preference is secondary to decrease in reinforcing properties of ethanol and not due to interference with satiety mechanisms, we compared the effect of two higher doses (10 and 20 µmol/kg, intraperitoneally, twice daily) of Goe 5438 on spontaneous preference for a non-caloric 0.04% saccharin solution in Sprague-Dawley rats. We observed a dose-dependent suppression of preference (by 44% and 58%, respectively) during the injection day, but not the subsequent 24 h period. However, Goe 5438 also significantly alleviated food pellet intake on the injection day. In conclusion, Goe 5438 produces potent and long-lasting inhibition of voluntary ethanol consumption, which may be secondary to attenuation of reinforcing properties of ethanol. Additionally, this particular Ca²⁺ channel inhibitor appears to have mild anorectic properties which may be conducive to acute suppression of alcohol intake.     

GABAergic Transmission in the Nucleus Accumbens Is Involved in the Termination of Ethanol Self-Administration in Rats

Long-Evans rats ( n = 12) were trained to lever-press on a fixed-ratio 4 schedule of reinforcement with ethanol (10% v/v) presented as the reinforcer. After implantation of bilateral stainless-steel guide cannulae aimed at the nucleus accumbens, site-specific microinjections of muscimol (1–30 ng) and bicuculline (1–10 ng) were tested for effects on ethanol-reinforced responding. Baseline response patterns were characterized by initial high rates that terminated abruptly after ∼20 min. Muscimol administration in the nucleus accumbens decreased the total number of ethanol-reinforced responses and obtained reinforcers. Bicuculline also decreased ethanol-reinforced responses and reinforcers at the highest dose tested. When a dose of bicuculline (1 ng) that was ineffective by itself was coadministered with an effective dose of muscimol (10 ng), the muscimol-induced decreases in responding were blocked. Analysis of response patterns showed that muscimol decreased ethanol self-administration by terminating responding, normally lasting 20 min, after ∼10 min with no changes in local response rate. Bicuculline decreased total responding by producing parallel, but nonsignificant, changes in time course and response rate. These data suggest that GABAergic transmission in the nucleus accumbens is involved in the termination, but not the onset or maintenance of ethanol self-administration. The specificity of this effect gives emphasis to the importance of measuring behavioral parameters, as well as products of behavior (such as intake volume) in the study of ethanol self-administration.     

Effect of Postnatal Ethanol Exposure on Expression of Differentiation Antigens of Murine Splenic Lymphocytes

Ethanol is a recognized immunosuppressive agent in the chronic alcoholic. However, the effects of ethanol exposure on the developing immune system have not been extensively investigated. This study evaluated the effects of early postnatal ethanol exposure, via breast milk, on splenic lymphocyte differentiation antigen expression in offspring reared by ethanol-fed mice. Maternal mice were fed a liquid diet containing 20% ethanol-derived calories during pregnancy (E-P), pregnancy and lactation (E-PL), or lactation (E-L). Ad libitumfed (C) and pair-fed (PF) control groups, fed a control liquid diet, were included. Expression of differentiation antigens on splenic lymphocytes from 21-day-old offspring reared by females in 1 of the 3 ethanol exposure conditions was evaluated by flow cytometry. Offspring reared by E-P females had similar numbers of splenic lymphocytes as offspring reared by C and pair-fed during pregnancy (PF-P) females. In contrast, offspring reared by E-PL and E-L females had fewer splenic lymphocytes than both PF-PL and PF-L (respectively), and C offspring. The number of Thy 1.2⁺, CD4⁺, CD8⁺, and IgG⁺ (B-cell) splenic lymphocytes was reduced in E-PL and E-L offspring compared with PF and C offspring. E-P offspring had fewer CD4⁺ and IgG⁺ splenic lymphocytes than C, but not PF-P, offspring. The percentage of Thy 1.2⁺ splenic lymphocytes was significantly reduced among E-PL and E-L offspring compared with PF-PL and PF-L (respectively), and C offspring. These results suggest that ethanol exposure of female mice during pregnancy, pregnancy and lactation, or lactation alone, alters the phenotypic development of splenic lymphocytes of offspring reared by these females. The greatest effect on differentiation antigen expression occurred when females consumed ethanol during the period of lactation. We speculate that direct exposure of the nursing offspring to ethanol via the breast milk was responsible for the reductions in specific splenic lymphocyte populations. These data demonstrate that mice reared by females fed ethanol during the early postnatal period have a marked depletion of each of the major subpopulations of splenic lymphocytes, and that Thy 1.2⁺ lymphocytes are differentially sensitive to ethanol.     

Chronic Ethanol Inhibits Inositol Metabolism in Specific Brain Regions

Many neurotransmitters and hormones in the nervous system transmit signals through receptors coupled to the poly-phosphoinositide (PI) signaling pathway. In this study, an in vivo protocol with (³H]inositol was used to examine the effect of chronic ethanol administration on inositol metabolism and poly-PI turnover in the cerebral cortex, hippocampus, and cerebellum of mouse brain. C57BL/6 mice were given a nutritionally complete liquid diet containing either ethanol (5%, w/v) or isocaloric sucrose for 2 months. Mice were injected intracerebrally with ^rH]inositol; after 16 or 24 hr, they were injected intraperitoneally with lithium (8 mEq/kg body weight) to inhibit the inositol monophosphatase (IP₁) activity. All mice were decapitated 4 hr after lithium injection. Labeled inositol phospholipids accounted for 16 to 23% of total labeled inositol in different regions of control mouse brain, and the percentages in the hippocampus were consistently higher than the cerebral cortex and cerebellum. In control mice, the percentages of labeled IP, after a 4-hr lithium treatment were 11.5%, 9.9%, and 3.7% for cerebral cortex, hippocampus, and cerebellum, respectively. Chronic ethanol feeding resulted in a significant (p < 0.05) decrease in the percent of labeled IP₁ and inositol phospholipids, and this effect was observed in the cerebral cortex and, to a lesser extent, hippocampus but not cerebellum. When ratios of labeled IP₁ were expressed against labeled inositol phospholipids as an index of the poly-PI turnover activity, significant decreases in IP/lipid ratios were observed in the cerebral cortex, but not the hippocampus or cerebellum. Although mice killed 24 + 4 hr after the last ethanol feeding would have experienced an 8-hr period of ethanol withdrawal, compared with the 16 + 4-hr group, no differences in IP/lipid ratios were observed between the two time groups. These results illustrate regional differences in the effect of chronic ethanol on inositol metabolism in the brain, but no difference in poly-PI turnover in brain due to ethanol withdrawal.     

Genotype-dependent effects of GABAergic agents on sedative properties of ethanol

Two lines of mice, selectively bred for differential sensitivity to the soporific effects of ethanol (ETOH), were administered GABAergic drugs in an effort to evaluate a role for GABA in ETOH sensitivity. ETOH sensitive Long-Sleep mice (LS) showed potentiated ETOH sedation when administered bicuculline, muscimol and aminooxyacetic acid (AOAA). ETOH-insensitive SS mice exhibited reduced ETOH sedation in the presence of the antagonists, bicuculline and picrotoxin, and potentiated sedation in the presence of muscimol and AOAA. These changes in narcosis duration were interpreted as central effects, since blood ethanol levels at waking from ETOH sedation varied with GABAergic drug treatment. Picrotoxin antagonized pentobarbital-induced nacrosis in both lines, but to a greater extent in SS mice. These and other experiments with a genetically heterogeneous stock suggest GABA involvement in genotype-dependent ETOH sensitivity, but do not support a simple role of GABA receptor involvement.