A study of sex differences in cognitive impairment in alcoholics using traditional and computer-based tests

Sex differences in the acute ethanol effects on object recognition memory: influence of estrous cycle

Effects of acute ethanol (EtOH) on memory depend on several factors, including type of behavioral task. Sex differences in EtOH effects have been reported in humans and animals, and recognition memory can be influenced by circulating sex hormones. The aim of this study was to investigate the influence of sex and estrous cycle in the acute effects of EtOH on novel object recognition memory in rats. Male and female Wistar rats were part of one of the groups: control, 0.6-g/kg EtOH and 1.8-g/kg EtOH (administered intraperitoneally before the training session). The estrous cycle was evaluated by vaginal smear. The task was conducted in an open field arena. During training, animals were exposed to two identical objects, and test sessions were performed 1 h (short-term) and 24 h (long-term) later. One of the objects was changed in each test. Increased novel object exploration was shown by male and female controls in the short- and long-term tests, respectively. In the short-term test, females did not show preference for the novel object, and EtOH 1.8 g/kg impaired performance in males. In the long-term test, both sexes showed object discrimination, and 1.8-g/kg EtOH reduced preference for the new object in male rats. The phase of the cycle, the performance on proestrus was worse compared with other phases, and EtOH failed to impair performance mainly on estrous. In conclusion, while male rats displayed ethanol-induced recognition memory deficit, female rats were unaffected by EtOH impairing effects. In addition, the performance of female rats was influenced by the estrous cycle phases.

Reactive, Adult Neurogenesis From Increased Neural Progenitor Cell Proliferation Following Alcohol Dependence in Female Rats

Hippocampal neurodegeneration is a consequence of excessive alcohol drinking in alcohol use disorders (AUDs), however, recent studies suggest that females may be more susceptible to alcohol-induced brain damage. Adult hippocampal neurogenesis is now well accepted to contribute to hippocampal integrity and is known to be affected by alcohol in humans as well as in animal models of AUDs. In male rats, a reactive increase in adult hippocampal neurogenesis has been observed during abstinence from alcohol dependence, a phenomenon that may underlie recovery of hippocampal structure and function. It is unknown whether reactive neurogenesis occurs in females. Therefore, adult female rats were exposed to a 4-day binge model of alcohol dependence followed by 7 or 14 days of abstinence. Immunohistochemistry (IHC) was used to assess neural progenitor cell (NPC) proliferation (BrdU and Ki67), the percentage of increased NPC activation (Sox2+/Ki67+), the number of immature neurons (NeuroD1), and ectopic dentate gyrus granule cells (Prox1). On day seven of abstinence, ethanol-treated females showed a significant increase in BrdU+ and Ki67+ cells in the subgranular zone of the dentate gyrus (SGZ), as well as greater activation of NPCs (Sox2+/Ki67+) into active cycling. At day 14 of abstinence, there was a significant increase in the number of immature neurons (NeuroD1+) though no evidence of ectopic neurogenesis according to either NeuroD1 or Prox1 immunoreactivity. Altogether, these data suggest that alcohol dependence produces similar reactive increases in NPC proliferation and adult neurogenesis. Thus, reactive, adult neurogenesis may be a means of recovery for the hippocampus after alcohol dependence in females.

Sex and gender-related differences in alcohol use and its consequences: Contemporary knowledge and future research considerations

AIMS

To review the contemporary evidence reflecting male/female differences in alcohol use and its consequences along with the biological (sex-related) and psycho-socio-cultural (gender-related) factors associated with those differences.

METHODS

MEDLINE, PubMed, Web of Science, SCOPUS, PsycINFO, and CINAHL databases were searched for relevant publications, which were subsequently screened for the presence/absence of pre-specified criteria for high quality evidence.

RESULTS

Compared to men, more women are lifetime abstainers, drink less, and are less likely to engage in problem drinking, develop alcohol-related disorders or alcohol withdrawal symptoms. However, women drinking excessively develop more medical problems. Biological (sex-related) factors, including differences in alcohol pharmacokinetics as well as its effect on brain function and the levels of sex hormones may contribute to some of those differences. In addition, differences in alcohol effects on behavior may also be driven by psycho-socio-cultural (gender-related) factors. This is evident by variation in the magnitude of differences in alcohol use between countries, decreasing difference in the rates of alcohol consumption in recent generations and other findings. Evidence indicates that both sex and gender-related factors are interacting with alcohol use in complex manner, which differentially impacts the risk for development of the behavioral or medical problems and alcohol use disorders in men and women.

CONCLUSIONS

Discovery of the mechanisms underlying biological (sex-related) as well as psycho-socio-cultural (gender-related) differences in alcohol use and related disorders is needed for development of personalized recommendations for prevention and treatment of alcohol use disorders and related problems in men and women.

Age differences in the expression of acute and chronic tolerance to ethanol in male and female rats

BACKGROUND

Ontogenetic differences in response to ethanol (EtOH) challenge have been observed under a variety of circumstances, including varying reports of developmental differences in the expression of tolerance to EtOH. The purpose of the present experiment was to further explore potential differences in acute (AT) and chronic (CT) tolerance expression between adolescent and adult, male and female Sprague-Dawley rats, using the social interaction test.

METHODS

AT and CT to the social suppressing effects of a moderate dose of EtOH was assessed in adolescent and adult rats following intraperitoneal injections of 2.0 g/kg EtOH or saline daily for 10 days. At test, adults and adolescents were challenged with 1.0 or 1.25 g/kg EtOH, respectively, with AT and CT assessed at 5 and 25 minutes postinjection using ratios of impairment to brain ethanol concentrations (BrECs) at each time period (CT) and within-session declines in impairment relative to BrECs (AT).

RESULTS

In adolescents, 10 days of EtOH pre-exposure resulted in evidence of CT at 25 minutes postinjection, perhaps associated with an enhanced expression of AT. Among adults, signs of CT were seen at 5 minutes postinjection in adults, and may reflect neuroadaptations unassociated with AT, as with evidence of tolerance emerging only in adult control animals repeatedly exposed to saline injection prior to EtOH challenge on test day. Sex differences in tolerance expression were not observed at either age.

CONCLUSIONS

Our results show ontogenetic differences between adolescents and adults in the short- and long-term neuroadaptations that they express in response to repeated perturbations with EtOH. Together these findings add age of exposure and time of testing within the intoxication period as critical variables to be considered when exploring the complex relationship between AT and CT.

Recovery of Short-Term Memory and Psychomotor Speed but Not Postural Stability With Long-Term Sobriety in Alcoholic Women

The authors assessed effects of extended abstinence on cognitive and motor function deficits previously observed in a group of alcoholic women (n = 43) initially tested after 15 weeks of sobriety. Alcoholic women were retested 1 and 4 years later, and control women were retested 3 years later. At Year 1, 14 of 23 returners had maintained sobriety, but they did not perform significantly better than relapsers; the group as a whole continued to show deficits relative to age norms. By Year 4, 13 of 14 returners had maintained sobriety for more than 30 months; as a group, these women had returned to normal levels on tests of memory and psychomotor speed but remained impaired in standing balance.

Epidemiology of substance use disorders in women

Significant gender differences exist in the prevalence of substance use disorders in the United States. There is a trend among boys and girls aged 12 to 17 years toward comparable rates of use and initiation for alcohol, cocaine, heroin, and tobacco. If this trend continues, over time there may be a narrowing of the male-to-female prevalence ratios of substance abuse in the older age groups. This possibility is particularly disturbing because women have a heightened vulnerability to medical, physical, mental, and social consequences of substance use. Women also carry additional unique risks during pregnancy because of the effect on neonates. In addition, they have certain gender-specific cancer risks. Given this and the declining age of initiation of substance use in women, prevention and treatment efforts especially geared toward women (eg, education of all medical and paramedical staff, screening in primary care clinics, detection of drug use early in pregnancy or before conception, brief interventions and treatment programs that integrate women's needs) are exceedingly important to stop and ultimately reverse this growing trend.

Sex differences in alcohol drinking patterns during forced and voluntary consumption in rats

Wistar rats were studied during forced and voluntary alcohol consumption, and continuous or periodic access to ethanol (6%) v/v with different availability of fluids. Absolute volume of alcohol consumption was not different between sexes in any condition; however, females consumed significantly more alcohol than males on a g/kg basis in all conditions. These differences were significantly more extensive during continuous free-choice to alcohol and water than during forced alcohol consumption. Females showed greater alcohol preference than males only during continuous free-choice to alcohol and water. During periodic free-choice to alcohol and water condition, alcohol consumption was distributed during more hours throughout the day in females than males. During periodic free-choice to alcohol and to an isocaloric sweetened solution (ISS), intakes of ISS were very high compared to regular intakes of daily water; nevertheless, alcohol consumption was maintained to similar levels observed in continuous free-choice to alcohol and water and represented almost 50% of regular daily consumes of water in males and females. Free-choice for alcohol and ISS modified the usual pattern of alcohol consumption during the daily light-dark cycle in males and females and reduced the time devoted to drinking alcohol compared to other conditions, in which similar intakes were observed. Results show that the extent of the higher alcohol consumption in females than males and the changes in patterns of alcohol intake were dependent on the nature of the ingestion schedule.

Voluntary alcohol consumption in vervet monkeys: individual, sex, and age differences

The patterns of voluntary alcohol consumption were studied in 35 vervet monkeys (Cercopithecus aethiops), classified into four groups. Each monkey showed a fairly steady rate during the studied period, resulting in individual differences that became more evident as the treatment evolved. Females showed higher alcohol intake frequencies than males. This sexual difference was maintained among adults and juveniles. Age differences were also observed: juveniles showed higher frequencies of intake than adults, both in general and in each sex group. Intake frequency was not related to age in prepubertal subjects, neither in general nor in each particular sex. The origin of these sex and age alcohol consumption differences remains to be studied, but differences in alcohol metabolism and factors related to puberty are possible influences.