The structural effects of Vitamin A deficiency on biological macromolecules due to ethanol consumption and withdrawal: An FTIR study with chemometrics.

The structural effects of vitamin A-deficiency were examined on the molecular profiles of biomolecules of male rat hippocampus during prolonged ethanol intake/withdrawal using FT-IR spectroscopy coupled with chemometrics. Liquid ethanol diet with/without vitamin A was maintained to adult rats for 3-months. The rats were decapitated at different ethanol withdrawal times and FT-IR spectra were obtained. Ethanol consumption/withdrawal produced significant changes in proteins' conformations, while having insignificant structural effects on lipids. In vitamin A deficiency, ethanol produced structural changes in lipids by lipid ordering especially in the early-ethanol withdrawal. Furthermore, an increase in lipid and protein content, saturated/unsaturated lipid ratio, a decrease in nucleic acids content and decrease in membrane fluidity were observed. These changes were less severe in the presence of Vitamin A. This study is clinically important for individuals with vitamin A deficiency because they have to be more cautious when consuming alcohol to protect themselves from cognitive dysfunctions.

Fetal alcohol and maternal stress modify the expression of proteins controlling postnatal development of the male rat hippocampus.

Background: Developing brains can partially get over prenatal alcohol exposure-related detrimental conditions by activating some mechanisms involved in survival. Objectives: This study aimed to shed light on the molecular correlates of compensatory mechanisms by examining temporal profiles in the expression of proteins controlling postnatal development in the rat hippocampus prenatally exposed to intubation stress/ethanol. Methods: Male pups were randomly assigned to age subgroups (n = 21/age) which were sacrificed on postnatal day (PD)1, PD10, PD30, and PD60. Ethanol (6 g/kg/day) were intragastrically intubated to the dams throughout 7-21 gestation days. The expression of neurogenesis and angiogenesis markers, extracellular matrix proteins, and growth-promoting ligands were examined by western blot. Results: The most rapid increase in the index of neuronal maturation was noted between PD10-PD30 (p < .05). Prenatal stress caused a decrease of neurogenesis markers at birth and an increase of their expressions at PD10 and PD30 to reach control levels (p < .001). The impact of fetal-alcohol was observed as a decrease in the expression of synaptic plasticity protein versican at birth (p < .001), an increase in the synaptic repulsion protein ephrin-B2 at PD10 (p < .001), and a decrease in the maturation of BDNF at PD30 (p < .001) with a decrease in the mature neuron markers at PD30 (p < .001) and PD60 (p = .005) which were compensated with upregulation of angiogenesis and increasing brevican expression, a neuronal maturation protein (p < .001). Conclusion: These data provide in vivo evidence for the potential therapeutic factors related to neurogenesis, angiogenesis, and neurite remodeling which may tolerate the alcohol/stress dependent teratogenicity in the developing hippocampus.

Prenatal ethanol intoxication and maternal intubation stress alter cell survival and apoptosis in the postnatal development of rat hippocampus.

It is well known that the fetal ethanol exposure and prenatal stress may have adverse effects on brain development. Interestingly, some morphological and functional recovery from their teratogenic effects that take place during brain maturation. However, mechanisms that underlie this recovery are not fully elucidated. The aim of this study was to examine whether the postnatal attenuation of fetal alcohol - and maternal stress­induced morphological and functional deficits correlates with compensatory changes in the expression/activation of the brain proteins involved in inflammation, cell survival and apoptosis. In this project, we investigated the hippocampus which belongs to the brain regions most susceptible to the adverse effects of prenatal ethanol exposure. Pregnant rat dams were administered ethanol (A) or isocaloric glucose solution (IC) by a gastric intubation during gestational days 7-20. The pure control group received ad libitum laboratory chow and water with no other treatment. The hippocampi of fetal-ethanol and control pups were examined at the postnatal day (PD)1, PD10, PD30 and PD60. Moderate fetal-ethanol exposure and prenatal intubation stress caused a significant increase in molecular factors relating to inflammation (iNOS) and cell survival/apoptosis pathways (PTEN, GSK-3 and ERK) at birth, with a rapid compensation from these developmental deficits upon removal of alcohol at PD10. Indeed, an increase in ERK1/2 and JNK1/2 activation at PD30 was observed with ethanol consumption. It indicates that the recovery process in A and IC brains started soon after the birth upon the ethanol and stressor withdrawal and continued until the adulthood.

The effects of repeated antibiotic administration to juvenile BALB/c mice on the microbiota status and animal behavior at the adult age.

Recent studies carried on germ -free (GF) animal models suggest that the gut microbiota (GM) may play a role in the regulation of anxiety, mood, and cognitive abilities such as memory and learning processes. Consistently, any treatment disturbing the gut microbiota, including the overuse of antibiotics, may influence the brain functions and impact behavior. In the present study, to address this issue, two wide-spectrum antibiotics (ampicillin and cefoperazone, 1 g/l) were repeatedly applied throughout a 6-week period to initially 21-day-old male BALB/c mice. Antibiotics were administered separately or in a mixed fashion. On the completion of the antibiotic treatment, all mice were subjected to the behavioral tests. The serum levels of corticosterone and brain-derived neurotropic factor (BDNF) were assessed. Gut microbiota profiles were obtained by using denaturing gradient gel electrophoresis system, DGGE, from fecal samples. Ampicillin had a greater impact on both, gut microbiota composition and mice behavior compared to cefoperazone. All antibiotic-treated groups manifested a decrease in the locomotor activity and reduced recognition memory. However, the ampicillin-treated groups showed a higher anxiety level as assessed by the open field and the elevated plus maze tests and an increased immobility (behavioral despair) in the forced swim test. Obtained results evidently show that in mice, a repeated antibiotic treatment applied during adolescence, parallel to the changes in GM, affects locomotor activity, affective behavior and cognitive skills in young adults with ampicillin specifically enhancing anxiety- and depressive-like responses. Lower levels of serum BDNF were not associated with cognitive impairment but with changes in affective-like behaviors. Repeated administration of neither ampicillin nor cefoperazone affected basal serum corticosterone levels. This is one of the few studies demonstrating changes in a behavioral phenotype of young-adult subjects who were previously exposed to a repeated antibiotic treatment.

Relationship between the hippocampal expression of selected cytochrome P450 isoforms and the animal performance in the hippocampus-dependent learning task.

Despite very extensive studies on the molecular mechanisms of memory formation, relatively little is known about the molecular correlates of individual variation in the learning skills within a random population of young normal subjects. The role of cytochrome P450 (CYP) enzymes in the brain also remains poorly understood. On the other hand, these enzymes are known to be related to the metabolism of substances important for neural functions including steroids, fatty acids, and retinoic acid. In the present study, we examined the potential correlation between the animals' performance in a place learning task and the levels of selected CYP isoforms (CYP2E1, CYP2D1 and CYP7A1) in the rat hippocampus. According to their performance, rats were classified as "good" learners (percent error/number of trials to criterion ≤ group mean - 3SEM) or "poor" learners (percent error/number of trials to criterion ≥ group mean + 3SEM). The CYP enzyme levels were determined by Western Blot at the early, intermediary and advanced stages of the task acquisition (day 4, day 8 and after reaching a performance criterion of 83% correct responses). In this study, as expected, CYP2E1 and CYP2D1 isoforms have been found in the rat hippocampus. However, a putative CYP7A1 isoform was also visualized. Hippocampal expression of these enzymes was shown to be dependent on the stage of learning and animals' cognitive status. In "good" learners compared to "poor" learners, significantly higher levels of CYP2E1 were found at the early stage of training, significantly higher levels of CYP2D1 were found at the intermediate stage of training, and significantly higher levels of CYP7A1-like protein were found after reaching the acquisition criterion. These findings suggest that the differential expression of some CYP isoforms in the hippocampus may have impact on individual learning skills and that different CYP isoforms may play different roles during the learning process.

Effects of prenatal binge-like ethanol exposure and maternal stress on postnatal morphological development of hippocampal neurons in rats.

BACKGROUND: Alcohol is one of the most commonly used drugs of abuse negatively affecting human health and it is known as a potent teratogen responsible for fetal alcohol syndrome (FAS), which is characterized by cognitive deficits especially pronounced in juveniles but ameliorating in adults. Searching for the potential morphological correlates of these effects, in this study, we compared the course of developmental changes in the morphology of principal hippocampal neurons in fetal-alcohol (A group), intubated control (IC group), and intact control male rats (C group) over a protracted period of the first two postnatal months. METHODS: Ethanol was administered to the pregnant Wistar dams intragastrically, throughout gestation days (GD) 7-20, at a total dose of 6g/kg/day resulting in the mean blood alcohol concentration (BAC) of 246.6±40.9mg/dl. Ten morphometric parameters of Golgi-stained hippocampal neurons (pyramidal and granule) from CA1, CA3, and DG areas were examined at critical postnatal days (PD): at birth (PD1), at the end of the brain growth spurt period (PD10), in juveniles (PD30), and in young adults (PD60). RESULTS: During postnatal development, the temporal pattern of morphometric changes was shown to be region-dependent with most significant alterations observed between PD1-30 in the CA region and between PD10-30 in the DG region. It was also parameter-dependent with the soma size (except for CA3 pyramids), number of primary dendrites, dendrite diameter, dendritic tortuosity and the branch angle demonstrating little changes, while the total dendritic field area, dendritic length, number of dendritic bifurcations, and spine density being highly increased in all hippocampal regions during the first postnatal month. Moderate ethanol intoxication and the maternal intubation stress during gestation, showed similar, transient effects on the neuron development manifested as a smaller soma size in granule cells, reduced dendritic parameters and lower spine density in pyramidal neurons at PD1. Full recovery from these effects took place within the first 10 postnatal days. CONCLUSIONS: This study showed regional and temporal differences in the development of different morphometric features of principal hippocampal neurons in intact subjects over a protracted 2-months postnatal period. It also demonstrated an overlap in the effects of a moderate fetal ethanol intoxication and a mild maternal stress produced by the intragastric intubation, a commonly used method of ethanol administration to the pregnant dams. Fast recovery from the adverse effects on the soma size, dendritic arborization and spines density observed at birth indicates towards the fetal ethanol/stress induced developmental retardation.

Comparison of spatial learning in the partially baited radial-arm maze task between commonly used rat strains: Wistar, Spargue-Dawley, Long-Evans, and outcrossed Wistar/Sprague-Dawley.

Strain-related differences in animals' cognitive ability affect the outcomes of experiments and may be responsible for discrepant results obtained by different research groups. Therefore, behavioral phenotyping of laboratory animals belonging to different strains is important. The aim of the present study was to compare the variation in allothetic visuospatial learning in most commonly used laboratory rat strains: inbred Wistar (W) and Sprague-Dawley (SD), outcrossed Wistar/Sprague-Dawley (W/SD), and outbred Long Evans (LE) rats. All rats were trained to the arbitrary performance criterion of 83 % correct responses in the partially baited 12-arm radial maze allowing for simultaneous evaluation of both working and reference memory. In the present study, testing albino versus pigmented and inbred versus outcrossed rats revealed significant strain-dependent differences with the inbred SD rats manifesting lower performance on all learning measures compared to other strains. On the other hand, the outcrossed W/SD rats showed a lower frequency of reference memory errors and faster rate of task acquisition compared to both LE and W rats, with W rats showing a lower frequency of working memory errors compared to other strains. In conclusion, albinism apparently did not reduce the animals' performance in the allothetic visuospatial learning task, while outcrossing improved the spatial learning. A differential effect of strain on the contribution of each error type to the animals' overall performance was observed. The strain-dependent differences were more pronounced between subpopulations of learning-deficient individuals ("poor" learners), and generally the reference memory errors contributed more to the final behavioral output than did the working memory errors.

Vitamin A deficiency induces structural and functional alterations in the molecular constituents of the rat hippocampus.

To date, no structural study has been carried out on the effects of vitamin A deficiency (VAD) on hippocampal macromolecules. Therefore, in the present study, the effect of dietary VAD on the structure, content and function of rat hippocampal molecules was investigated using Fourier transform IF spectroscopy. Male Wistar rats were randomly divided into three groups: an experimental group maintained on a vitamin A-deficient liquid diet (VAD, n 7); a control group maintained on a vitamin A-supplemented liquid diet (CON, n 9); a pure control group maintained on standard solid laboratory chow (PC, n 7). The PC group was included in the study to ensure that the usage of liquid diet did not influence the outcomes of VAD. Both the CON and PC groups were successfully discriminated from the VAD group by principal component analysis and hierarchical cluster analysis. The spectral analysis indicated a significant decrease in the contents of saturated and unsaturated lipids, cholesteryl esters, TAG and nucleic acids in the VAD group when compared with the CON group (P≤ 0·05). In addition, a significant decrease in membrane fluidity and a significant increase in lipid order (e.g. acyl chain flexibility) were observed in the VAD group (P≤ 0·001). The results of the artificial neural network analysis revealed a significant decrease in the α-helix structure content and a significant increase in the turn and random coil structure contents, indicating protein denaturation, in the VAD group when compared with the CON and PC groups (P≤ 0·05). Dietary exclusion of vitamin A for 3 months apparently had an adverse impact on compositional, structural and dynamical parameters. These changes can be due to increased oxidative stress, confirming the antioxidant protection provided by vitamin A when used as a dietary supplement at low-to-moderate doses.

Investigation into the effects of prenatal alcohol exposure on postnatal spine development and expression of synaptophysin and PSD95 in rat hippocampus.

Ethanol is known as a potent teratogen responsible for the fetal alcohol syndrome characterized by cognitive deficits especially pronounced in juveniles but ameliorating in adults. Since the mechanisms of these deficits and following partial recovery are not fully elucidated, the aim of the present study was to investigate the process of synaptogenesis in the hippocampus over the first two months of life in control and fetal-alcohol rats. Ethanol was delivered to the pregnant dams by intragastric intubation throughout 7-21 gestation days at the daily dose of 6g/kg generating a mean blood alcohol level of 246.6±40.9mg/dl on gestation day 20. The spine densities as well as the expression of pre- and postsynaptic proteins, synaptophysin (SYP) and PSD-95 protein, were evaluated for three distinct hippocampal regions: CA1, CA2+3, and DG and four postnatal days: PD1, PD10, PD30 and PD60, independently. Our results confirmed an intensive synaptogenesis within the brain spurt period (first 10 postnatal days), however, the temporal pattern of changes in the SYP and PSD-95 expression was different. The ethanol exposure during half of the 1st and the whole 2nd human trimester equivalent resulted in an overall trend toward lower values of synaptic indices at PD1 with a fast recovery from these deficits observed already at PD10. At PD30, around the age when the most pronounced behavioral deficits have been previously reported in juvenile fetal-alcohol subjects, no significant changes were found in either the hippocampal levels of synaptic proteins or in the spine density in principal hippocampal neurons.

Examination of age-dependent effects of fetal ethanol exposure on behavior, hippocampal cell counts, and doublecortin immunoreactivity in rats.

Ethanol is known as a potent teratogen having adverse effects on brain and behavior. However, some of the behavioral deficits caused by fetal alcohol exposure and well expressed in juveniles ameliorate with maturation may suggest some kind of functional recovery occurring during postnatal development. The aim of this study was to reexamine age-dependent behavioral impairments in fetal-alcohol rats and to investigate the changes in neurogenesis and gross morphology of the hippocampus during a protracted postnatal period searching for developmental deficits and/or delays that would correlate with behavioral impairments in juveniles and for potential compensatory processes responsible for their amelioration in adults. Ethanol was delivered to the pregnant dams by intragastric intubation throughout 7-21 gestation days at daily dose of 6 g/kg. Isocaloric intubation and intact control groups were included. Locomotor activity, anxiety, and spatial learning tasks were applied to juvenile and young-adult rats from all groups. Unbiased stereological estimates of hippocampal volumes, the total number of pyramidal and granular cells, and double cortin expressing neurons were carried out for postnatal days (PDs) PD1, PD10, PD30, and PD60. Alcohol insult during second trimester equivalent caused significant deficits in the spatial learning in juvenile rats; however, its effect on hippocampal morphology was limited to a marginally lower number of granular cells in dentate gyrus (DG) on PD30. Thus, initial behavioral deficits and the following functional recovery in fetal-alcohol subjects may be due to more subtle plastic changes within the hippocampal formation but also in other structures of the extended hippocampal circuit. Further investigation is required.

Hippocampal levels of ChAT, PKA, phospho-PKA and phospho-CaMKIIα but not CaMKIIα positively correlate with spatial learning skills in rats.

Despite very extensive investigations on molecular processes underlying memory formation, there are very few studies examining potential differences in the brain biochemistry between "good" and "poor" learners belonging to a random population of young animals. In the present study, an attempt was made to correlate individual variation in spatial learning in young-adult Long-Evans rats with hippocampal levels of protein kinase A (PKA), calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα), and choline acetyltransferase (ChAT). Additionally, in order to indirectly estimate the activity of CaMKIIα and PKA, hippocampal levels of their phosphorylated forms (pCaMKIIα and pPKA) were assessed using Western blot technique. Rats were classified as "good" and "poor" learners on the basis of their performance in a partially baited 12-arm radial maze. The biochemical assays did not reveal a significant difference in the basal hippocampal levels of the CaMKIIα, however, the level of pCaMKIIα, was significantly higher in "good" learners. Also, hippocampal levels of both PKA and pPKA, as well as that of ChAT, were significantly higher in "good" as compared to "poor" learners. Our results suggest that the differences in the expression level of PKA and ChAT (but not of CaMKIIα), as well as the differences in the activation of both PKA and CaMKIIα, may contribute to the individual variation in learning skills and episodic-like memory in a random population of young-adult subjects.

Effects of early postnatal alcohol exposure on the developing retinogeniculate projections in C57BL/6 mice.

Previous studies on the adverse effects of perinatal exposure to ethanol (EtOH) on the developing visual system mainly focused on retinal and optic nerve morphology. The aim of the present study was to investigate whether earlier reported retinal and optic nerve changes are accompanied by anomalies in eye-specific fiber segregation in the dorsal lateral geniculate nucleus (dLGN). C57BL/6 mice pups were exposed to ethanol by intragastric intubation at either 3 or 4 g/kg from postnatal days (PD) 3-10, the third trimester equivalent to human gestation. Control (C) and intubation control (IC) groups not exposed to ethanol were included. On PD9, retinogeniculate projections were labeled by intraocular microinjections of cholera toxin-ß (CTB) either conjugated to Alexa 488 (green) or 594 (red) administrated to the left and right eye, respectively. Pups were sacrificed 24 h after the last CTB injection. The results showed that ethanol exposure decreased the total number of dLGN neurons and significantly reduced the total dLGN projection as well as the contralateral and ipsilateral projection areas.

Correlation between hippocampal levels of neural, epithelial and inducible NOS and spatial learning skills in rats.

In the present study, to better understand the role of different nitric oxide synthase (NOS) isoforms in hippocampus-dependent forms of learning, we examined the expression of neural, endothelial, and inducible NOS in the hippocampus of young-adult rats classified as "poor" and "good" learners on the basis of their performance in the partially baited 12-arm radial maze. Taking into consideration strain-dependent differences in learning skills and NOS expression, experiments were performed on two different lines of laboratory rats: the inbred Wistar (W) and the outcrossed Wistar/Spraque-Dawley (W/S) line. The hippocampal levels of NOS proteins were assessed by Western Blotting. In the present study, genetically more homogenous W rats showed a slower rate of learning compared to the genetically less homogenous outcrossed W/S rats. The deficient performance in the W rat group compared to outcrossed W/S rats, and in "poor" learners of both groups compared to "good" learners was due to a higher percentage of reference memory errors. The overall NOS levels were significantly higher in W group compared to outcrossed W/S rats. In both rat lines, the rate of learning positively correlated with hippocampal levels of nNOS and negatively correlated with iNOS levels. Hippocampal eNOS levels correlated negatively with animals' performance but only in the W rats. These results suggest that all 3 NOS isoforms are implemented but play different roles in neural signaling.

Differential effect of age on the brain fatty acid levels and their correlation with animal cognitive status in mice.

The aim of the present study was to investigate the possible relationship between the levels of various fatty acids (FA) in the brain and learning indices in aged (22­23 months old) and young (2­3 months old) female Swiss Webster (SW) mice. The mice were classified as "good" or "poor" learners based on their performance in a spatial learning task: the Morris Water Maze. The levels of several FA including palmitic, stearic, oleic, linoleic, arachidonic (AA), and docosahexaenoic acid (DHA), were measured by gas chromatography in tissue samples from four different brain areas: hippocampus, frontal cortex, striatum and hypothalamus. The results of behavioral tests confirmed a decline in learning skills with age. However, a great individual variation was revealed in learning scores between aged subjects, indicating that biological aging does not always parallel chronological aging. The relative levels of particular fatty acids across the four examined brain structures were very similar. Interestingly, only in the hypothalamus was the DHA omega-3 acid level significantly higher in young mice compared to the old mice. For the remaining brain structures, no significant correlations were found between the DHA level and the animal's age and/or cognitive status. A significant correlation between learning performance and fatty acid levels in the brain was found only for AA in the young mice hippocampus, a structure known to be critical for spatial learning and memory. The AA level was significantly lower in young "good" learners compared to both young "poor" and old "good" learners with young "good" learners showing significantly better performance than the two other groups. These findings contribute to the current debate on the value of DHA supplementation as an effective protective treatment against senile dementia and the potential role of AA in memory deficits.

Rosiglitazone treatment reduces hippocampal neuronal damage possibly through alleviating oxidative stress in chronic cerebral hypoperfusion.

Oxygen free radicals and lipid peroxidation may play significant roles in the progress of injury induced by chronic cerebral hypoperfusion of the central nervous system. Rosiglitazone, a well known activator of PPARγ, has neuroprotective properties in various animal models of acute central nervous system damage. In the present study, we evaluate the possible impact of rosiglitazone on chronic cerebral hypoperfused-rats in regard to the levels of oxidative stress, reduced glutathione, and hippocampal neuronal damage. Chronic cerebral hypoperfusion was generated by permanent ligation of both common carotid arteries of Wistar rats for one month. Animals in treatment group were given rosiglitazone orally at doses of 1.5, 3, or 6mg/kg per day of the 1month duration. The treatment significantly lowered the levels of both malondialdehyde and neuronal damage, while elevated the reduced glutathione level markedly. These findings suggest that the beneficial effect of rosiglitazone on hypoperfusion-induced hippocampal neuronal damage might be the result of inhibition of oxidative insult.

Effects of early postnatal exposure to ethanol on retinal ganglion cell morphology and numbers of neurons in the dorsolateral geniculate in mice.

BACKGROUND: The adverse effects of fetal and early postnatal ethanol intoxication on peripheral organs and the central nervous system are well documented. Ocular defects have also been reported in about 90% of children with fetal alcohol syndrome, including microphthalmia, loss of neurons in the retinal ganglion cell (RGC) layer, optic nerve hypoplasia, and dysmyelination. However, little is known about perinatal ethanol effects on retinal cell morphology. Examination of the potential toxic effects of alcohol on the neuron architecture is important because the changes in dendritic geometry and synapse distribution directly affect the organization and functions of neural circuits. Thus, in the present study, estimations of the numbers of neurons in the ganglion cell layer and dorsolateral geniculate nucleus (dLGN), and a detailed analysis of RGC morphology were carried out in transgenic mice exposed to ethanol during the early postnatal period. METHODS: The study was carried out in male and female transgenic mice expressing yellow fluorescent protein (YFP) controlled by a Thy-1 (thymus cell antigen 1) regulator on a C57 background. Ethanol (3 g/kg/d) was administered to mouse pups by intragastric intubation throughout postnatal days (PDs) 3 to 20. Intubation control (IC) and untreated control (C) groups were included. Blood alcohol concentration was measured in separate groups of pups on PDs 3, 10, and 20 at 4 different time points, 1, 1.5, 2, and 3 hours after the second intubation. Numbers of neurons in the ganglion cell layer and in the dLGN were quantified on PD20 using unbiased stereological procedures. RGC morphology was imaged by confocal microscopy and analyzed using Neurolucida software. RESULTS: Binge-like ethanol exposure in mice during the early postnatal period from PDs 3 to 20 altered RGC morphology and resulted in a significant decrease in the numbers of neurons in the ganglion cell layer and in the dLGN. In the alcohol exposure group, out of 13 morphological parameters examined in RGCs, soma area was significantly reduced and dendritic tortuosity significantly increased. After neonatal exposure to ethanol, a decrease in total dendritic field area and an increase in the mean branch angle were also observed. Interestingly, RGC dendrite elongation and a decrease in the spine density were observed in the IC group, as compared to both ethanol-exposed and pure control subjects. There were no significant effects of alcohol exposure on total retinal area. CONCLUSIONS: Early postnatal ethanol exposure affects development of the visual system, reducing the numbers of neurons in the ganglion cell layer and in the dLGN, and altering RGCs' morphology.

The effects of short-term chronic ethanol intoxication and ethanol withdrawal on the molecular composition of the rat hippocampus by FT-IR spectroscopy.

BACKGROUND: The numerous adverse effects of ethanol abuse and ethanol withdrawal on biological systems are well documented. Conversely, the understanding of the molecular mechanisms underlying these pathological effects is still incomplete. This study was undertaken to investigate the effects of short-term chronic ethanol administration and ethanol withdrawal on the molecular structure and function of hippocampal tissue, a brain region important for mnemonic processes and known to be highly susceptible to ethanol intoxication. METHODS: Ethanol was administered to adult Wistar rats by intragastric intubation for 15 days with a stepwise increase in the daily dose from 6 to 12 g/kg body weight, with the highest dose delivered for the last 2 days only. The total daily dose of ethanol was divided into 3 equal portions administered 4 hours apart. Animals were sacrificed by decapitation at 4, 24, and 72 hours after the last ethanol administration to examine potential effects of ethanol intoxication and ethanol withdrawal. Ethanol-related molecular changes were monitored by Fourier transform infrared (FT-IR) spectroscopy. RESULTS: Significant changes in the hippocampal content, structure, and function of lipids, proteins, and nucleic acids were recorded under ethanol intoxication. Seventy-two hours after the cessation of ethanol administration, during the late phase of withdrawal, alterations in the macromolecules' content and conformational changes in protein and nucleic acid structure ameliorated, while the changes in macromolecular ratios, lipid order, and dynamics aggravated. CONCLUSIONS: Our results suggest that 15 days of binge-like drinking resulting in the high blood alcohol concentration (varying in the dose-dependent manner between 253 and 606 mg/dl) produced a strong physical dependence manifested mainly by the changes in lipid profiles pointing toward withdrawal-induced oxidative stress. These results show that ethanol withdrawal may cause equal to or even more severe brain damage than the ethanol itself, which should be considered when designing antialcohol therapies.

Neuroprotective efficacy of the peroxisome proliferator-activated receptor-γ ligand in chronic cerebral hypoperfusion.

Chronic cerebral hypoperfusion can cause learning and memory impairment and neuronal damage resembling the effects observed in vascular dementia. PPAR-γ agonists were shown to modulate inflammatory response and neuronal death following cerebral ischemia. The present study was designed to evaluate possible neuroprotective effects of rosiglitazone, a PPAR-γ agonist, in rat model of chronic cerebral hypoperfusion. Cerebral hypoperfusion was induced by permanent bilateral occlusion of the common carotid arteries. Oral administration of rosiglitazone (1.5, 3, and 6 mg/kg/day) or vehicle was carried out for 5 weeks, starting one week before the surgery. Cognitive performance was assessed using the Morris water maze. The density of S100B protein-immunoreactive astrocytes and the OX-42-labeled microglial activation were estimated. Synaptogenesis was also evaluated by the measurement of synaptophysin, the pre-synaptic vesicular protein, level via western blotting technique. Cerebral hypoperfusion for 30 days induced a significant cognitive impairment along with hyperactivation of both microglial and astroglial cells, and reduction of synaptophysin level. Rosiglitazone treatment (3 and 6 mg/kg) not only suppressed the activation of astrocytes and microglia markedly but also alleviated the impairment of memory and increased the synaptophysin level. In conclusion, our results suggest that the chronic administration of rosiglitazone significantly prevents chronic cerebral hypoperfusion-induced brain damage, at least, partly through suppressing glial activation and preserving synaptic plasticity. Thus, it appears that rosiglitazone may be a promising pharmacological agent in the development of therapeutic approaches for the prevention or treatment of cerebrovascular diseases.

Chronic intracerebroventricular NGF administration improves working memory in young adult memory deficient rats.

Although the beneficial effects of nerve growth factor (NGF) in age-related memory deficits are well documented, the therapeutic role of this neurotrophin in memory deficits occurring in young subjects remains unclear. In the present study, the effect of chronic NGF administration on spatial working memory was investigated in young adult memory deficient Wistar rats. Memory deficient rats were selected on the basis of their preoperative performance in delayed matching-to-position task (DMTP) carried out in the eight-arm radial maze. The delay between sample and test choices was prolonged stepwise from 10s, to 1, 5, and eventually 15 min. Rats that performance at the longest 15-min delay was at least 3 S.E.M. above the group mean were classified as "poor learners". They were randomly assigned to either Control or NGF group, and treated with either vehicle solution (artificial cerebrospinal fluid) or NGF at the total dose of 40 microg/rat. Intracerebroventricular (icv) drug infusion was made continuously over 28 days at the rate of 0.25 microl/h using Alzet 2004 osmotic mini-pump. The postoperative training included the same stages as the preoperative one. No significant between-group difference in the postoperative performance was noted at the shortest delay of 10s that could be bridged by the immediate memory. Conversely, at all three longer delays, postoperative performance in the NGF group was significantly better compared to control rats. The present study thus shows that NGF may have beneficial effects in memory-deficient young adults.

Individual variation in the spatial reference and working memory assessed under allothetic and idiothetic orientation cues in rat.

The present study was designed to examine which kind of memory: reference or working, better correlates with individual variation in rats' spatial learning abilities. To answer this question two groups of rats were trained to an arbitrary criterion in a partially baited 12-arm radial maze under two different experimental conditions: with or without allothetic cues. After 10 days break, rats were examined under the same conditions for memory retention. Within- and between-group variation in the length of training to criterion, and in the frequency of reference and working memory errors were analysed. The present experiment confirmed the facilitating effect of the presence of distal visual cues on place learning in rats. Task-dependent (between-group) differences in the rate of learning were attributed to differences in the frequency of reference memory errors. Conversely, within-group variation in the rate of task acquisition reflected individual variation in the frequency of working memory errors. These results were looked upon from an evolutionary perspective. Low correlation between reference and working memory errors confirms that these two types of memory have different mechanisms. The fact that differences in the rate of learning were not paralleled by the differences in the memory retention supports the notion that memory acquisition and memory retention are two independent processes.