Chronic ad libitum ethanol exposure impairs corticolimbic and cerebellar structural neuroplasticity in rats

Chronic, but not acute, ethanol exposure impairs central hypercapnic ventilatory drive in bullfrog tadpoles

Alcohol use disorder (AUD) is characterized by compulsive drinking, which is thought to be mediated by effects of chronic intermittent ethanol exposure on the dorsal striatum, the input nucleus of the basal ganglia. Despite significant efforts to understand the impact of ethanol on the dorsal striatum, the rich diversity of striatal cell types and multitude of ethanol targets expressed by them necessitates an unbiased, discovery-based approach. In this study, we used single-nuclei RNA-sequencing (snRNA-seq; n = 86,715 cells) to examine the impact of chronic intermittent ethanol exposure on the dorsal striatum in C57BL/6 male and female mice. We detected 462 differentially expressed genes at FDR < 0.05, the majority of which were mapped to spiny projection neurons (SPNs), the most prominent cell type in the striatum. Gene co-expression network analysis and functional annotation of differentially expressed genes revealed down-regulation of postsynaptic intracellular signaling cascades in SPNs. Inflammation-related genes were down-regulated across many neuronal and non-neuronal cell types. Gene set enrichment analyses also pointed to altered states of rare cell types, including the induction of angiogenesis-related genes in vascular cells. A gene module down-regulated specifically in canonical SPNs was enriched for calcium-signaling genes and components of glutamatergic synapses, as well as for genes associated with genetic risk for AUD. Genetic perturbations of six of this module's hub genes - Foxp1, Bcl11b, Pde10a, Rarb, Rgs9, and Itgr1 - had causal effects on its expression in the mouse striatum and/or on the broader set of differentially expressed genes in alcohol-exposed mice. These data provide important clues as to the impact of ethanol on striatal biology and provide a key resource for future investigation.

Effects of acute and chronic ethanol exposure on the behavior of adult zebrafish ( Danio rerio)

After administration, ethanol and its metabolites go through the kidneys and are excreted into urine. The kidney seems to be the only vital organ generally spared in chronic alcoholics. Therefore, we investigated the multiple effects of chronic ethanol exposure on renal function tests and on oxidative stress related parameters in the kidney. Chronic ethanol (1.6 g ethanol/ kg body weight/ day) exposure did not show any significant change in relative weight (g/ 100g body weight) of kidneys, serum calcium level or glutathione s-transferase activity. However, urea and creatinine concentration in serum, and TBARS level in kidney elevated significantly, while reduced glutathione content and activities of glutathione peroxidase, glutathione reductase and superoxide dismutase diminished significantly after 12 weeks of ethanol exposure. Catalase activity showed increased activity after 4 weeks of ethanol exposure and decreased activity after 12 weeks of ethanol exposure. Genesis of renal ultrastructural abnormalities after 12 weeks of ethanol exposure may be important for the development of functional disturbances. This study revealed that chronic ethanol exposure for longer duration is associated with deleterious effects in the kidney.

Ethanol exposure impairs mammalian reproductive function. However, the mechanisms are not fully understood. Adult female rats were given an ethanol or a calorically matched control diet. A third group was given a liquid nonethanol diet. Half the animals were killed at 2 weeks (short chronic) and the other half at 2 months (long chronic), all on the day of proestrous on the basis of daily vaginal smears. The major effect of ethanol feeding was disruption in the estrous cycle. Although all of the pair-fed animals continued to cycle, 40% of the ethanol rats in the short chronic study had disruption of their cycles. In the long chronic study, 83% of the ethanol animals had abnormal cycling, in contrast to 16% of the pair-fed controls. The nature of the cycle disruption was prolongation of diestrous, with an increased time interval between proestrous surges. In four ethanol-fed rats, there was complete cessation of the estrous cycle. However, ethanol did not decrease ovarian or uterine weight. Ethanol significantly increased serum estradiol in the short chronic but not long chronic study, whereas progesterone was unchanged. Ethanol did cause a significant reduction in circulating insulin-like growth factor. The major effect of both short chronic and long chronic ethanol exposure was disruption of the estrous regularity, leading to a decreased number of proestrous surges. Part of the mechanism of this disruption might be a transient estrogen increase or a decrease in circulating insulin-like growth factor.

Background : Ethanol exposure impairs mammalian reproductive function. However, the mechanisms are not fully understood. Methods: Adult female rats were given an ethanol or a calorically matched control diet. A third group was given a liquid nonethanol diet. Half the animals were killed at 2 weeks (short chronic) and the other half at 2 months (long chronic), all on the day of proestrous on the basis of daily vaginal smears. Results: The major effect of ethanol feeding was disruption in the estrous cycle. Although all of the pair-fed animals continued to cycle, 40% of the ethanol rats in the short chronic study had disruption of their cycles. In the long chronic study, 83% of the ethanol animals had abnormal cycling, in contrast to 16% of the pair-fed controls. The nature of the cycle disruption was prolongation of diestrous, with an increased time interval between proestrous surges. In four ethanol-fed rats, there was complete cessation of the estrous cycle. However, ethanol did not decrease ovarian or uterine weight. Ethanol significantly increased serum estradiol in the short chronic but not long chronic study, whereas progesterone was unchanged. Ethanol did cause a significant reduction in circulating insulin-like growth factor. Conclusions: The major effect of both short chronic and long chronic ethanol exposure was disruption of the estrous regularity, leading to a decreased number of proestrous surges. Part of the mechanism of this disruption might be a transient estrogen increase or a decrease in circulating insulin-like growth factor.

Chronic ethanol exposure increases peripheral-type benzodiazepine receptors in brain

Chronic ethanol exposure facilitates facial-evoked MLI-PC synaptic transmission via nitric oxide signaling pathway in vivo in mice

A depression in cytochrome c oxidase (COX) activity occurs following chronic embryonic ethanol exposure in vivo. The aim of this study was to examine the effect of chronic ethanol exposure on COX activity in isolated cardiac cells maintained in vitro. Additionally, the mechanism by which ethanol produces an impairment in COX activity was evaluated by examining mitochondrial gene expression. Spontaneously beating cardiac myocyte cultures were established from 10-day embryonic chick hearts. Various concentrations of ethanol (0-250 mM) were introduced at the time of plating and cells were harvested over 7 days. COX activity was determined in myocyte homogenates. The levels of nuclear-encoded (COXIV) and mitochondrial-encoded (COXII) subunit proteins were measured by Western blotting. Relative levels of mitochondrial DNA and the mitochondrially-encoded COXIII mRNA were determined by Southern and Northern blotting. A consistent decrease in COX activity in ethanol-exposed cardiac myocytes of approximately 30% was observed with an ethanol concentration of 25 mM. Increasing the ethanol concentration to 250 mM produced only a minor enhancement of this effect, while severely decreasing cellular viability. The content of the mitochondrially-encoded COXII subunit was reduced by ethanol exposure, while that of the nuclear-encoded COXIV subunit was unchanged. The content of the mitochondrially-encoded COXIII mRNA was unchanged by ethanol exposure. However, prolonged ethanol exposure produced an increase in mitochondrial DNA levels in cardiac myocytes. Ethanol exposure of cardiac myocytes produces deficits in COX activity in the absence of systemic variables, indicating that ethanol has a direct effect on cardiac mitochondria. The ethanol-induced decrease in COX activity is correlated with a specific decrease in at least one mitochondrially-encoded gene product, COXII. No changes were observed in the level of the nuclear-encoded COXIV subunit, indicating that expression of this nuclear-encoded gene is not impaired by ethanol exposure.

Long-term alcohol consumption has been linked to structural and functional brain abnormalities. Furthermore, with persistent exposure to ethanol (EtOH), nutrient deficiencies often develop. Thiamine deficiency is a key contributor to alcohol-related brain damage and is suspected to contribute to white matter pathology. The expression of genes encoding myelin proteins in several cortical brain regions is altered with EtOH exposure. However, there is limited research regarding the impact of thiamine deficiency on myelin dysfunction. A rat model was used to assess the impact of moderate chronic EtOH exposure (CET; 20% EtOH in drinking water for 1 or 6months), pyrithiamine-induced thiamine deficiency treatment (PTD), both conditions combined (CET-PTD), or CET with thiamine injections (CET+T) on myelin-related gene expression (Olig1, Olig2, MBP, MAG, and MOG) in the frontal and parietal cortices and the cerebellum. The CET-PTD treatments caused the greatest suppression in myelin-related genes in the cortex. Specifically, the parietal cortex was the region that was most susceptible to PTD-CET-induced alterations in myelin-related genes. In addition, PTD treatment, with and without CET, caused minor fluctuations in the expression of several myelin-related genes in the frontal cortex. In contrast, CET alone and PTD alone suppressed several myelin-related genes in the cerebellum. Regardless of the region, there was significant recovery of myelin-related genes with extended abstinence and/or thiamine restoration. Moderate chronic EtOH alone had a minor effect on the suppression of myelin-related genes in the cortex; however, when combined with thiamine deficiency, the reduction was amplified. There was a suppression of myelin-related genes following long-term EtOH and thiamine deficiency in the cerebellum. However, the suppression in the myelin-related genes mostly occurred 24h after EtOH removal or following thiamine restoration; within 3weeks of abstinence or thiamine recovery, gene expression rebounded.

The central nucleus of the amygdala (CeA) is implicated in alcohol use disorder (AUD) and AUD-associated plasticity. The CeA is a primarily GABAergic nucleus that is subdivided into lateral and medial compartments with genetically diverse subpopulations. GABAA receptors are heteromeric pentamers with subunits conferring distinct physiological characteristics. GABAA receptor signaling in the CeA has been implicated in ethanol-associated plasticity; however, population-specific changes in inhibitory signaling and subunit expression remain unclear. Here, we combined electrophysiology with single-cell gene expression analysis of population markers and GABAA receptor subunits to examine population-specific changes in inhibitory control in male and female rats following chronic ethanol exposure. We found that chronic ethanol exposure and withdrawal produced global changes in GABAA receptor subunit expression at the transcript and protein levels, increased excitability in female CeA neurons, and increased inhibitory synaptic transmission in male CeA neurons. When we examined CeA neurons at the single-cell level we found heterogenous populations, as previously reported. We observed ethanol-induced increases in excitability only in somatostatin neurons in the CeA of females, decreases in excitability only in the protein kinase C delta (PKCd) population in males, and ethanol-induced increases in inhibitory transmission in male PKCd and calbindin 2-expressing CeA neurons. There were no population-specific differences in GABAA receptor (Gabr) subunits in males but reduced GabrA5 expression in female somatostatin neurons. Collectively, these findings suggest that defined CeA populations display differential ethanol sensitivity in males and females, which may play a role in sex differences in vulnerability to AUD or expression of AUD pathology.SIGNIFICANCE STATEMENT The CeA is involved in the effects of ethanol in the brain; however, the population-specific changes in CeA activity remain unclear. We used recordings of CeA neuronal activity and single-cell gene expression to examine population-specific changes in inhibitory control in male and female rats following chronic ethanol exposure and found sex- and population-specific effects of chronic ethanol exposure and withdrawal. Specifically, female CeA neurons displayed increased excitability in the somatostatin CeA population, whereas male CeA neurons displayed increased inhibitory control in both PKCd and calbindin populations and decreased excitability in the PKCd population. These findings identify CeA populations that display differential sensitivity to ethanol exposure, which may contribute to sex differences in vulnerability to alcohol use disorder.

Chronic ethanol exposure has been described in humans to produce a series of long and short term electrophysiological consequences. Interpretation of the electrophysiological findings in human subjects, however, is made difficult due to concomitant factors, such as nutritional status, premorbid functioning and differences in genetic susceptibility to the effects of ethanol. In the present study, electroencephalograms (EEGs) and auditory event related potentials (ERPs) were utilized to explore the short and longer term effects of chronic ethanol exposure in rats. Rats were continuously exposed to ethanol vapors for a period for 1 month. This treatment produced a mean blood ethanol level of 178 +/- 13.86 mg%. EEGs and ERPs were subsequently collected at 10 min, 24 h, and 2 weeks following termination of ethanol exposure. Significant changes in the EEGs and ERPs of these rats could be demonstrated. EEG amplitude increases, as quantified by spectral analysis, were most prominent at the 24 h time period, perhaps reflecting a state of "rebound excitability". EEG responses were normalized in ethanol-treated rats by 2 weeks post-withdrawal. In contrast, reductions in the N1 and P2 amplitudes of the rat ERPs were prominent after chronic ethanol exposure and following 2 weeks withdrawal, suggesting that ethanol may produce some longer term effects on response to ERP stimuli. Taken together, these studies suggest that ethanol may produce differential effects on EEG and ERPs and that this model may provide a useful substrate for the evaluation of the mechanisms underlying the effects of chronic ethanol exposure.

The overall objective of this study was to analyze the effects of a combined prenatal and postnatal (entire gestational human chronic drinking model) ethanol exposure on T-cell development in mice. Specifically, this study evaluated the effects of chronic exposure to prenatal ethanol on lymphocyte makeup and proliferative capabilities of postnatal offspring's (4 and 12 weeks) peripheral lymphoid tissues. Chronic exposure regimens were conducted over the entire gestational period and through postnatal day 14 or 21. Thymus, spleen, and intestinal intraepithelial lymphocytes were harvested and analyzed by flow cytometry for percentages of T-cell subsets. Splenic lymphocytes were also analyzed for their ability to proliferate in response to a T-cell mitogen. Limited effects of chronic ethanol exposure were seen.

Effects of chronic ethanol exposure on dorsal medial striatal neurons receiving convergent inputs from the orbitofrontal cortex and basolateral amygdala.

Withdrawal from chronic ethanol exposure increases postsynaptic glutamate function of insular cortex projections to the rat basolateral amygdala