Juvenile variable stress modulates, in female but not in male Wistar rats, ethanol intake in adulthood

Early stress can increase vulnerability to psychopathological disorders, including substance use disorders. The effects of stress in the juvenile period of the rat, that extends between weaning and the onset of adolescence (equivalent to late human childhood), have received little attention. This study assessed short and long-term behavioral effects of juvenile stress, with a focus on effects on ethanol intake. Male and female Wistar rats were exposed to variable stress (restraint, elevated platform, forced swimming, and social instability) or to restraint stress only, between postnatal days 26 to 29 (PDs 26-29). During adolescence, patterns of anxiety (PD 31) and depression (PD 33), ethanol intake (PDs 36-45) and behavioral sensitivity to the effects of acute stress (PD 47) were evaluated. In adulthood, alcohol ingestion was assessed through two-bottle ethanol intake tests (PDs 75-85). An additional experiment measured blood ethanol levels after a limited access intake session in adolescence. Exposure to juvenile variable stress exerted very mild effects in adolescence, but reduced ethanol ingestion in adulthood, in females only. Ethanol intake during the limited access session was significantly correlated to blood alcohol levels. The results indicate that a schedule of juvenile variable stress that did not significantly alter anxiety-related behaviors induced, nonetheless, sexually dimorphic effects on ethanol intake in adulthood. Early stress exposure that reduced alcohol intake in Wistar rats has been associated with changes on brain opioid and dopamine receptors. These results highlight the impact of early stress exposure on adult female ethanol consumption and its possible underlying neurobiological changes, involving opioid and dopamine receptors.

Neurobehavioral alterations induced by third-trimester gestation-equivalent ethanol exposure are inhibited by folate administration

Prenatal ethanol exposure (PEE) causes several neurobehavioral impairments in the fetus. Postnatal days (PDs) 4-9 in rodents are considered equivalent to the third trimester of gestation in humans. This period is characterized by high rates of synaptogenesis and myelination and the maturation of key structures and transmitter systems. Nutritional supplements, such as folate, have gained attention as putative treatments to mitigate detrimental effects of PEE. Folate is crucial for DNA synthesis and amino acid metabolism and heightens antioxidant defenses. The present study examined neurobehavioral effects of the concurrent administration of folate (20 mg/kg/day) and ethanol (5 g/kg/day) during PDs 4-9 in male and female Wistar rats. During PDs 16-18, the rat pups were tested for anxiety-like and exploratory activity in the light-dark box (LDB), open field (OF), and concentric square field (CSF) tests. After weaning, they were tested for sucrose preference and ethanol intake. Neonatal ethanol exposure reduced body weight in infancy but did not enhance ethanol self-administration or significantly affect performance in the OF or LDB. Neonatal ethanol exposure also reduced sucrose intake in the preference test and increased shelter-seeking in the CSF, and folate significantly inhibited these effects. The present findings suggest that folate, a treatment that is devoid of serious side effects, can ameliorate some neurobehavioral effects of PEE.

Influence of Drinking Context and Age of Onset on Alcohol Consumption Patterns and Motivations Among Uruguayan Adults

Objectives

An early age of drinking onset is linked to a greater likelihood of alcohol-related problems. Alcohol use occurs in places featuring characteristic social groups, and different drinking contexts are associated with different levels of alcohol-related outcomes. Drinking context may affect drinking motives, expectations or alcohol-related outcomes in concert with individual-level variables. The study aimed to examine how the preferred drinking context and age of the first drink affects the occurrence and volume of alcohol use, drinking motives and alcohol-related expectations.

Methods

This cross-sectional study was conducted at Faculty of Veterinary Medicine, University of the Republic, Montevideo, Uruguay, from September 2020 to January 2021. Uruguayan citizens ≥18 years old were asked about their preferred drinking context, the age of first alcohol use and alcohol consumption frequency. In addition, the Drinking Motives Questionnaire and Alcohol Outcome Expectancies Questionnaire were used.

Results

A total of 752 Uruguayan citizens were included. The distribution of alcohol consumption across social contexts was not influenced by the age of first alcohol use. Those who began drinking early and endorsed solitary drinking reported higher frequency of drinking (P <0.05) and coping motives (P <0.05) than any other group. Those who drank at parties reported more conformity motives than most of the groups (P <0.01). An early age of drinking onset was associated with greater enhancement and social motives (P <0.05) and higher alcohol expectancies for stress reduction and social facilitation (P <0.005).

Conclusion

Solitary drinking as a high-risk drinking context is likely to interact with the age of first alcohol use, suggesting that drinking in specific contexts is associated with specific drinking motivations and expectancies. This study represents progress towards exploring factors that influence alcohol consumption among a broader range of socio-cultural populations.