Brain mitochondrial alterations after chronic alcohol consumption

The aim of this study was to demonstrate the existence of alterations in glutathione and cholesterol homeostasis in brain mitochondria from alcoholic rats. Glutathione concentration decreased, whereas oxidized glutathione and cholesterol contents increased in these organelles, suggesting the ethanol-induced generation of reactive oxygen species, and the impairment of mitochondrial uptake of glutathione, possibly due to the increase in cholesterol deposition. The release of apoptogenic proteins was increased after stimulating mitochondria from the brain of alcoholic rats with atractyloside. As a conclusion, chronic alcohol consumption might sensitize brain mitochondria to apoptotic stimuli, and promote the subsequent release of apoptotic proteins.     

Increased number of beta-adrenergic receptors on cells of the rat adenohypophysis after thyroid hormone administration

The authors studied the effect of administration of thyroid hormones on the beta-adrenergic receptors of rat adenohypophyseal cells. The administration of triiodothyronine and thyroxine was followed by an increase in specific binding for 3H-dihydroalprenolol. No significant differences were found in cyclic adenosine monophosphate levels before and after isoprenaline stimulation. The significance of changes in these receptors for the hyperplastic reaction after oestrogens is discussed with reference to the inhibitory effect of the thyroid hormones on hyperplasia of the adenohypophyseal cells after the administration of oestradiol.     

The ultrastructural characteristics of the corticotropic cells of the rat adenohypophysis

Ultrastructural characteristics of corticotropic cells have been studied on serial semithin and ultrathin sections of the hypophysis from intact rats by the immunofluorescence and electron microscopic methods. It is shown that the population of corticotropic cells is heterogeneous and consists of degranulated, moderate granulated, hypergranulated cells and transitional forms among them. Ultrastructurally corticotropic cells correspond to Siperstein-Nakayama's ACTH cells. Kurosumi-Kobayashi "corticotrophs" fail to react with the antiserum to ACTH, so they have not regard for its production.     

Argentaffin cells in human adenohypophysis]

Appropriate techniques such as Bodian's method demonstrate numerous argyrophilic cells in the adenohypophysis of man. These cells were shown by subsequent staining methods to be chromophobe cells. Furthermore, beta cells may also be impregnated by the method of Bodian, but display a much less intense argyrophilia than the first mentioned cell type. Both cellular forms react positively to diazotation techniques used to demonstrate indol radicals. This findings should be related, for instance, with the demonstration of indolamines in beta cells by the technique of induced fluorescence.     

Benzodiazepine receptor loss in brains of mice after chronic alcohol consumption

Benzodiazepine receptors in crude mitochondrial fractions of whole brains of mice were decreased in density and affinity after the animals had consumed alcohol in liquid diets for 7 months and then solid laboratory food for 1 month. These mice were compared with control mice pair-fed with the same liquid diet containing isocaloric amounts of sucrose. The maximal binding (B_max) of alcohol-treated mice was found to be decreased by 12% from 1580 to 1340 fmol/mg protein and the dissociation constant (K_D) was increased from 1.4 to 2.0 nM. Acute intoxication lasting for 2 weeks had no effect. It is hypothesized that once brain damage in the form of decreased synaptic receptor numbers and affinity has been induced by chronic alcohol consumption, this change in receptors could in itself become a cause of self-perpetuating alcohol abuse. Specifically the loss of anxiolytic receptors caused by chronic alcohol consumption could enhance anxiety and the compensatory consumption of the sedative alcohol.     

Dopamine-inhibited adenylate cyclase in female rat adenohypophysis

A dopamine-inhibited adenylate cyclase has been demonstrated in anterior pituitary gland of adult female rats, lactating and not lactating. This inhibitory effect was completely GTP dependent. In contrast, in the adenohypophysis of male rats, dopamine had no detectable effect on adenylate cyclase activity. In female rats the inhibition of the enzyme appears mediated by specific dopaminergic receptors: the effect of dopamine was mimicked by the dopaminergic agonists apomorphine and the ergot derivative CH 29–717, while norepinephrine was much less potent. On the other hand, the dopaminergic antagonists trifluoperazine and sulpiride competitively antagonized the dopamine inhibition of the adenylate cyclase. The possibility that the dopamine-inhibited enzyme is located in mammotrophs appears supported 1) by its observation in the female rat pituitary, which contains this type of cells in much larger proportion than the male gland (33–38% vs. < 5%); 2) by the pharmacological similarity between the dopaminergic receptors mediating the adenylate cyclase inhibition (this work) and those regulating prolactin release (which have been characterized in previous studies). The well known inhibition of prolactin release brought about by dopamine could therefore be mediated, at least in part, by a decrease in the intracellular level of cAMP.     

Semi-automatic morphometric analysis of secretory granules in the cells of the rat adenohypophysis

The authors carried out a morphometric analysis--using a semi-automatic system for image analysis--of the secretory granules in the cells of the Wistar rat adenohypophysis. They evaluated the mean diameter (CIRCLE D), maximum diameter (MAX D), the factor of circular form (PE FORM) and the harmonic factor of form (HAR FORM). They also computed the coefficient of correlation between CIRCLE D and PE FORM and the percentual distribution of the values according to mean diameter.     

Nongranulated cells in the mouse adenohypophysis

Summary Follicular cells in the mouse adenohypophysis were studied electron microscopically. These elements appear to be very similar to the marginal cells that delineate both sides of the hypophyseal cleft.The mouse differs from most other species in that the follicular cells in the pars distalis and the marginal cells look completely inactive in young, intact animals. This makes the mouse exceptionally favorable for correlating morphological changes in the cells of both types with changes in the physiological state of the animal. Different treatments applied in the present investigation all induced morphological reactions in the follicular and/or marginal cells; these reactions were generally similar. Thus, morphological changes in the follicular or marginal cells should be considered as general phenomena accompanying many changes in the physiological state of the animal, rather than as a specific result of the treatment applied.In three experiments, the follicular and marginal cells were involved in the digestion of waste material from other cells. It is suggested that the morphological changes in the other experiments should also be interpreted as signs of such an activity.In the pars tuberalis of the young, intact mouse the follicular cells may show characteristics that in the pars distalis are found only under experimental conditions. Therefore, the follicular cells in this part of the hypophysis are probably in an active state.     

Monoamines and peptidergic Gomori-positive neurosecretory cells of the paraventricular nucleus of the rat hypothalamus in chronic alcohol consumption

For 6 months the rats were kept on 20 degrees ethanol. Then, the rats could choose whether to drink alcohol (A) or water. The rats formed 2 groups: those preferring A and those preferring water. The control rats were kept on water. The function of hypothalamus monoamine- and peptidergic systems were disturbed following chronic A treatment. Alcohol-preferring, unlike water-preferring rats, have revealed higher hypothalamus levels of serotonin and lower levels of dopamine and noradrenaline, which correlated with changes in fluorescence intensity of hypothalamus noradrenaline structures and were accompanied by remarkable disturbances in nonapeptide neurohormone transport in the paraventricular nucleus region.     

Effect of maternal alcohol consumption on the fetal thyroid in the rat

To investigate the effect of maternal alcohol consumption on the development of the fetal thyroid gland, Sprague-Dawley rats were given 20% ethanol for 4 weeks prior to mating and 30% ethanol throughout gestation. Pair-fed controls received an isocaloric amount of corn starch and chow, with water ad libitum, and ad libitum controls received rat chow and water. On Days 17, 18, 19, and 20 of gestation, the fetuses were weighed and the fetal thyroids were removed for histometric observation. On Days 19 and 20, the fetal thyroids of alcohol-exposed fetuses weighed significantly less than those of the two control groups, but more than the control thyroids 1 day earlier. Maternal alcohol consumption caused a significant decrease in both the follicular cell height and the follicle diameter of the fetal thyroid on all days examined. In the alcohol group on Days 19 and 20 of gestation, the cell height was less than, and the follicle diameter was approximately equal to those in the two controls 2 days earlier. These results indicate that, as a consequence of maternal alcohol consumption, growth of the fetal thyroid gland is retarded, and there are indications of fetal hypothyroidism, as seen from the histometric data. This latter is suggestive of a retarded thyrotropic activity of the fetal pituitary gland.     

Long-term alcohol consumption increases matrix metalloproteinase-2 activity in rat aorta.

Altered degradation of extracellular matrix (ECM) underlies vascular remodeling, a hallmark in the pathogenesis of cardiovascular diseases including hypertension and aneurysmal dilatation. Although alcohol is recognized as a risk factor for certain cardiovascular disease states, its role in vascular remodeling has not been completely explored. We studied the effect of chronic alcohol consumption on upregulation of the enzymatic activity of matrix metalloproteinase-2 (MMP-2) as a possible pathway for large vessel remodeling. For this purpose, female rats were placed on one of three diets: a modified Lieber-DeCarli liquid diet containing 35% ethanol-derived calories, a pair-fed liquid diet with ethanol replaced by isocaloric maltose-dextrin, or a standard rat pellet. Weekly blood alcohol concentration averaged 117+/-7.9 mg/dl for the alcohol-fed rats. At 2, 4, and 72 weeks, aortas were removed and processed for measuring MMPs activity by gelatin zymography. Aortic extracts from rats on long-term (72 weeks), but not the short-term (2 and 4 weeks), alcohol diets showed increased MMP-2 activity. Furthermore, histochemical analysis of the aortas showed distinct disruption of the elastic fibers only in the 72 weeks alcohol-fed rats, compared to the control animals. These observations demonstrate that long-term alcohol consumption up-regulates MMP-2 activity, which is coincident with the alteration of aortic ECM composition through the degradation of vascular elastin components.     

Effects of alcohol consumption on mitochondrial aldehyde dehydrogenase isoenzymes in rat liver

The effects of long-term and short-term exposure of rats to ethanol on aldehyde dehydrogenase (ALDH) activity in the liver mitochondria were investigated. The specific activities of mitochondrial high Km ALDH and low Km ALDH after the prolonged administration of ethanol were both increased to levels about 2.5 times that of the control group. In contrast, high Km and low Km ALDH showed maximum activity 12 h after administration of a single large dose of ethanol, increasing 21 and 4.4 times, respectively, over the level in the control group. When ethanol was administered for a long time, the two ALDH isoenzyme levels showed approximately the same increase, while the high Km ALDH level was more significantly increased than the low Km ALDH level after a single large dose. These results suggest that the high Km ALDH level of the outer membrane was increased as a result of a transient increase in the level of acetaldehyde around the liver mitochondria after a single large dose of ethanol, and that high Km ALDH plays an important role in acetaldehyde metabolism. However, when ethanol was administered for a long time, the mitochondria were exposed to low concentrations of acetaldehyde over a long time, leading to an increase in levels of low and high Km ALDH in the matrix.     

Diurnal changes in the 3-hydroxybutyrate dehydrogenase activity of rat liver mitochondria during chronic alcohol consumption and after cessation

The activity of 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) in the isolated rat liver mitochondria changes but slightly during 24 h. In animals which were fed 10% ethanol solution for 3.5 months the enzyme activity varies within the daily cycle: maximum--at 10 p. m., minimum--at 1-4 p. m. and at 4-7 a. m.; the average daily activity gets three times lower. The cessation of the alcohol consumption makes average daily activity of the enzyme only two times higher, but the character of daily changes in the activity is different: the maximum is observed at 4-7 p. m., the minimum at 4-7 a. m.     

Npy deletion in an alcohol non-preferring rat model elicits differential effects on alcohol consumption and body weight

Neuropeptide Y(NPY) is widely expressed in the central nervous system and influences many physiological processes.It is located within the rat quantitative trait locus(QTL) for alcohol preference on chromosome 4.Alcohol-nonpreferring(NP) rats consume very little alcohol,but have significantly higher NPY expression in the brain than alcohol-preferring(P) rats.We capitalized on this phenotypic difference by creating an Npy knockout(KO) rat using the inbred NP background to evaluate NPY effects on alcohol consumption.Zinc finger nuclease(ZNF) technology was applied,resulting in a 26-bp deletion in the Npy gene.RT-PCR,Western blotting and immunohistochemistry confirmed the absence of Npy mRNA and protein in KO rats.Alcohol consumption was increased in Npy~(+/-) but not Npy~(-/-) rats,while Npy~(-/-) rats displayed significantly lower body weight when compared to Npy~(+/+) rats.In whole brain tissue,expression levels of Npy-related and other alcohol-associated genes,Npy1 r,Npy2r,Npy5 r,Agrp,Mc3 r,Mc4r,Crh and CrMr,were significantly greater in Npy~(-/-) rats,whereas Pome and Crhr2 expressions were highest in Npy~(+/-) rats.These findings suggest that the NPY-system works in close coordination with the melanocortin(MC) and corticotropin-releasing hormone(CRH) systems to modulate alcohol intake and body weight.     

Moderate alcohol consumption and loss of cerebellar Purkinje cells.

OBJECTIVE--To examine the dose-response effect of alcohol consumption on the number of cerebellar Purkinje cells. DESIGN--A prospective necropsy study combined with detailed reports on use of alcohol from a relative or friend. The number of Purkinje cells was counted in the anterior midsagittal section of the cerebellar vermis, the area of which was measured by computer assisted morphometry. SETTING--Department of forensic medicine, University of Helsinki. SUBJECTS--66 men, aged 35 to 69 years, subjected to medicolegal necropsy because of sudden or violent death. The average all year daily alcohol consumption over the year was 0 to 10 g in 17 men, 11 to 80 g in 24 men, and more than 80 g in 25 men. MAIN OUTCOME MEASURES--Number of Purkinje cells, alcohol consumption. RESULTS--The numbers and density of Purkinje cells in the cross section of vermis showed a consistent but weak decrease with increasing daily alcohol intake but not with age. A wide variation in the cell counts was observed, especially in men drinking more than 80 g, suggesting differences in the susceptibility to effects of alcohol. Compared with men drinking 40 g or less, a long term moderate consumption of an average of 41 to 80 g daily was associated with a significant average loss of 242 (95% confidence interval 45 to 439) Purkinje cells (15.2%) from a mean of 1583 to 1341 cells. In those drinking 81 to 180 g the average loss was 535 (259 to 811) cells (33.4%) to a mean of 1048 cells. The density of cells in the cross section of vermis also fell significantly by 0.9 cell/mm (0.1 to 1.7) when the daily consumption exceeded 40 g and by 1.4 cell/mm (0.3 to 2.5) when the intake was 81 to 180 g. Only three cases (4.5%) in the series showed macroscopical cerebellar atrophy. CONCLUSION--Long term intake of moderate doses of alcohol daily for 20-30 years may damage the cerebellum before the onset of macroscopical atrophy. Despite distinct individual differences an all year average daily alcohol intake of 41-80 g results in a risk of significant loss of Purkinje cells.     

Hypoplasia of the adenohypophysis in a Sprague-Dawley rat

Pathological examination performed on a male 70-day-old Sprague-Dawley rat revealed formation of a large cyst in the hypophysis. The cyst, which completely occupied the adenohypophyseal area, was lined by the epithelial cells. Small masses of the adenohypophyseal cells were occasionally seen to sprout from the cyst wall epithelium.     

Immunocytological study of the gonadotrophic and thyrotrophic cells of the rat adenohypophysis]

On paraffin or semi-thin sections various anti-LH or anti-TSH sera stain indifferently all the thyrotrophs and the gonadotrophs. Inversely anti-beta-TSH, anti-beta-LH or anti-beta-FSH purified sera permit the discrimination of these two cell populations. The constancy of fixation of the anti-beta-LH and anti-beta-FSH sera on all the gonadotrophs gives evidence of their ability to produce both FSH and LH. However in a few female rats the central gonadotrophs are stained more weakly by anti-beta-FSH serum than by anti-beta-LH serum. The purification of the antisera by adjunction of hormonal antigens (alpha subunits or heterologous hormone) does not enable, with the PAP technique on thin sections, a selective staining of the secretory granules of the thyrotrophs or of the gonadotrophs.